From 01a97ee966d15fc4660cabf1e43fcccfbe6b370f Mon Sep 17 00:00:00 2001
From: Sascha Lisson <sl@q60.de>
Date: Wed, 17 Jun 2026 10:52:28 +0200
Subject: [PATCH] fix(tables): AssertionException in EditorCell_GridCell.paint
 for headless components

The sticky headers feature tries to read the scroll position which isn't available in case of
headless components. The screenshots can then not be created by the generator.
---
 CHANGELOG.md                                  |   1 +
 .../de.itemis.mps.extensions.changelog.mps    |  35 ++++
 .../de/slisson/mps/tables/runtime/cells.mps   | 168 +++++++++++++++---
 3 files changed, 184 insertions(+), 20 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5830cdae3a..37ec53de16 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ The format is *loosely* based on [Keep a Changelog](https://keepachangelog.com/e
 ### Fixed
 
 - *de.q60.mps.shadowmodels.runtime* [SM_CommandHelper](http://127.0.0.1:63320/node?ref=r%3A97875f9c-321e-405e-a344-6d3deab2bdba%28de.q60.mps.shadowmodels.runtime.smodel%29%2F7709076119916772664) now only runs commands on fully initialized projects.
+- *de.slisson.mps.tables* AssertionException in EditorCell_GridCell.paint for headless components prevented screenshots
 
 ## May 2026
 
diff --git a/code/solutions/de.itemis.mps.extensions.changelog/models/de.itemis.mps.extensions.changelog.mps b/code/solutions/de.itemis.mps.extensions.changelog/models/de.itemis.mps.extensions.changelog.mps
index 92440a32d6..5c9c223dac 100644
--- a/code/solutions/de.itemis.mps.extensions.changelog/models/de.itemis.mps.extensions.changelog.mps
+++ b/code/solutions/de.itemis.mps.extensions.changelog/models/de.itemis.mps.extensions.changelog.mps
@@ -284,6 +284,41 @@
             <property role="3oM_SC" value="projects." />
           </node>
         </node>
+        <node concept="2DRihI" id="1wC2mc97oO5" role="15bAlk">
+          <property role="2RT3bR" value="0" />
+          <node concept="15Ami3" id="1wC2mc97oSS" role="1PaTwD">
+            <node concept="37shsh" id="1wC2mc97oSU" role="15Aodc">
+              <node concept="1dCxOk" id="1wC2mc97oVa" role="37shsm">
+                <property role="1XweGW" value="7e450f4e-1ac3-41ef-a851-4598161bdb94" />
+                <property role="1XxBO9" value="de.slisson.mps.tables" />
+              </node>
+            </node>
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFC" role="1PaTwD">
+            <property role="3oM_SC" value="AssertionException" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFD" role="1PaTwD">
+            <property role="3oM_SC" value="in" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFE" role="1PaTwD">
+            <property role="3oM_SC" value="EditorCell_GridCell.paint" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFF" role="1PaTwD">
+            <property role="3oM_SC" value="for" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFG" role="1PaTwD">
+            <property role="3oM_SC" value="headless" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFH" role="1PaTwD">
+            <property role="3oM_SC" value="components" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pFI" role="1PaTwD">
+            <property role="3oM_SC" value="prevented" />
+          </node>
+          <node concept="3oM_SD" id="1wC2mc97pHT" role="1PaTwD">
+            <property role="3oM_SC" value="screenshots" />
+          </node>
+        </node>
       </node>
     </node>
     <node concept="15bmVD" id="1gkZC7ksSqH" role="15bmVC">
diff --git a/code/tables/languages/de.slisson.mps.tables/runtime/models/de/slisson/mps/tables/runtime/cells.mps b/code/tables/languages/de.slisson.mps.tables/runtime/models/de/slisson/mps/tables/runtime/cells.mps
index 18414abc5d..aade3cc560 100644
--- a/code/tables/languages/de.slisson.mps.tables/runtime/models/de/slisson/mps/tables/runtime/cells.mps
+++ b/code/tables/languages/de.slisson.mps.tables/runtime/models/de/slisson/mps/tables/runtime/cells.mps
@@ -69,6 +69,7 @@
     <import index="nivk" ref="1ed103c3-3aa6-49b7-9c21-6765ee11f224/java:jetbrains.mps.editor.runtime.descriptor(MPS.Editor/)" />
     <import index="tpc2" ref="r:00000000-0000-4000-0000-011c8959029e(jetbrains.mps.lang.editor.structure)" />
     <import index="9p8b" ref="r:2a738fcb-23b4-4d1d-9f52-870528559e28(de.slisson.mps.tables.runtime.selection)" />
+    <import index="qqrq" ref="498d89d2-c2e9-11e2-ad49-6cf049e62fe5/java:com.intellij.ui.components(MPS.IDEA/)" />
   </imports>
   <registry>
     <language id="18bc6592-03a6-4e29-a83a-7ff23bde13ba" name="jetbrains.mps.lang.editor">
@@ -9053,6 +9054,129 @@
               </node>
             </node>
             <node concept="2tJIrI" id="5prQSJ52grL" role="jymVt" />
+            <node concept="3clFb_" id="17a3YpxfeA" role="jymVt">
+              <property role="TrG5h" value="getViewport" />
+              <node concept="3uibUv" id="17a3YpxKuK" role="3clF45">
+                <ref role="3uigEE" to="qqrq:~JBViewport" resolve="JBViewport" />
+              </node>
+              <node concept="3Tm6S6" id="17a3Ypyuth" role="1B3o_S" />
+              <node concept="3clFbS" id="17a3YpxfeE" role="3clF47">
+                <node concept="3cpWs8" id="17a3YpyTua" role="3cqZAp">
+                  <node concept="3cpWsn" id="17a3YpyTub" role="3cpWs9">
+                    <property role="TrG5h" value="editorComponent" />
+                    <node concept="3uibUv" id="17a3YpyTuc" role="1tU5fm">
+                      <ref role="3uigEE" to="exr9:~EditorComponent" resolve="EditorComponent" />
+                    </node>
+                    <node concept="10QFUN" id="17a3YpyTud" role="33vP2m">
+                      <node concept="3uibUv" id="17a3YpyTue" role="10QFUM">
+                        <ref role="3uigEE" to="exr9:~EditorComponent" resolve="EditorComponent" />
+                      </node>
+                      <node concept="1rXfSq" id="17a3YpyTuf" role="10QFUP">
+                        <ref role="37wK5l" to="g51k:~EditorCell_Basic.getEditorComponent()" resolve="getEditorComponent" />
+                      </node>
+                    </node>
+                  </node>
+                </node>
+                <node concept="3SKdUt" id="17a3Yp$L95" role="3cqZAp">
+                  <node concept="1PaTwC" id="17a3Yp$L96" role="1aUNEU">
+                    <node concept="3oM_SD" id="17a3Yp$L97" role="1PaTwD">
+                      <property role="3oM_SC" value="EditorComponent.getViewport" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_cSR" role="1PaTwD">
+                      <property role="3oM_SC" value="throws" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_cV3" role="1PaTwD">
+                      <property role="3oM_SC" value="an" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_cV4" role="1PaTwD">
+                      <property role="3oM_SC" value="AssertionException" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rnw" role="1PaTwD">
+                      <property role="3oM_SC" value="for" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rnx" role="1PaTwD">
+                      <property role="3oM_SC" value="headless" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rpW" role="1PaTwD">
+                      <property role="3oM_SC" value="components" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rsB" role="1PaTwD">
+                      <property role="3oM_SC" value="and" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_ruM" role="1PaTwD">
+                      <property role="3oM_SC" value="EditorComponent.hasUI" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rEP" role="1PaTwD">
+                      <property role="3oM_SC" value="is" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_rEQ" role="1PaTwD">
+                      <property role="3oM_SC" value="package-private." />
+                    </node>
+                  </node>
+                </node>
+                <node concept="3SKdUt" id="17a3Yp_BPa" role="3cqZAp">
+                  <node concept="1PaTwC" id="17a3Yp_BPb" role="1aUNEU">
+                    <node concept="3oM_SD" id="17a3Yp_N$8" role="1PaTwD">
+                      <property role="3oM_SC" value="Searching" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_ZoB" role="1PaTwD">
+                      <property role="3oM_SC" value="the" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3Yp_ZoD" role="1PaTwD">
+                      <property role="3oM_SC" value="viewport" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1$l" role="1PaTwD">
+                      <property role="3oM_SC" value="in" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1$m" role="1PaTwD">
+                      <property role="3oM_SC" value="the" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1$n" role="1PaTwD">
+                      <property role="3oM_SC" value="ancestors" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1CW" role="1PaTwD">
+                      <property role="3oM_SC" value="seems" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1Fn" role="1PaTwD">
+                      <property role="3oM_SC" value="to" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1HM" role="1PaTwD">
+                      <property role="3oM_SC" value="be" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1HN" role="1PaTwD">
+                      <property role="3oM_SC" value="the" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1JY" role="1PaTwD">
+                      <property role="3oM_SC" value="cleanest" />
+                    </node>
+                    <node concept="3oM_SD" id="17a3YpA1Mp" role="1PaTwD">
+                      <property role="3oM_SC" value="workaround." />
+                    </node>
+                  </node>
+                </node>
+                <node concept="3cpWs6" id="17a3Yp$lq2" role="3cqZAp">
+                  <node concept="10QFUN" id="17a3Yp$lq4" role="3cqZAk">
+                    <node concept="2YIFZM" id="17a3Yp$lq5" role="10QFUP">
+                      <ref role="37wK5l" to="dxuu:~SwingUtilities.getAncestorOfClass(java.lang.Class,java.awt.Component)" resolve="getAncestorOfClass" />
+                      <ref role="1Pybhc" to="dxuu:~SwingUtilities" resolve="SwingUtilities" />
+                      <node concept="3VsKOn" id="17a3Yp$lq6" role="37wK5m">
+                        <ref role="3VsUkX" to="qqrq:~JBViewport" resolve="JBViewport" />
+                      </node>
+                      <node concept="37vLTw" id="17a3Yp$lq7" role="37wK5m">
+                        <ref role="3cqZAo" node="17a3YpyTub" resolve="editorComponent" />
+                      </node>
+                    </node>
+                    <node concept="3uibUv" id="17a3Yp$lq8" role="10QFUM">
+                      <ref role="3uigEE" to="qqrq:~JBViewport" resolve="JBViewport" />
+                    </node>
+                  </node>
+                </node>
+              </node>
+              <node concept="2AHcQZ" id="17a3YpybgL" role="2AJF6D">
+                <ref role="2AI5Lk" to="mhfm:~Nullable" resolve="Nullable" />
+              </node>
+            </node>
+            <node concept="2tJIrI" id="17a3YpwZLa" role="jymVt" />
             <node concept="3clFb_" id="5prQSJ52grM" role="jymVt">
               <property role="TrG5h" value="paint" />
               <node concept="3Tm1VV" id="5prQSJ52grN" role="1B3o_S" />
@@ -9116,19 +9240,14 @@
                     </node>
                   </node>
                 </node>
-                <node concept="3cpWs8" id="1oWwpQDO4e1" role="3cqZAp">
-                  <node concept="3cpWsn" id="1oWwpQDO4e2" role="3cpWs9">
-                    <property role="TrG5h" value="editorComponent" />
-                    <node concept="3uibUv" id="1oWwpQDO4e3" role="1tU5fm">
-                      <ref role="3uigEE" to="exr9:~EditorComponent" resolve="EditorComponent" />
+                <node concept="3cpWs8" id="17a3YpB4eu" role="3cqZAp">
+                  <node concept="3cpWsn" id="17a3YpB4ev" role="3cpWs9">
+                    <property role="TrG5h" value="viewport" />
+                    <node concept="3uibUv" id="17a3YpASUO" role="1tU5fm">
+                      <ref role="3uigEE" to="qqrq:~JBViewport" resolve="JBViewport" />
                     </node>
-                    <node concept="10QFUN" id="1oWwpQDO4e4" role="33vP2m">
-                      <node concept="3uibUv" id="1oWwpQDO4e5" role="10QFUM">
-                        <ref role="3uigEE" to="exr9:~EditorComponent" resolve="EditorComponent" />
-                      </node>
-                      <node concept="1rXfSq" id="1oWwpQDO4e6" role="10QFUP">
-                        <ref role="37wK5l" to="g51k:~EditorCell_Basic.getEditorComponent()" resolve="getEditorComponent" />
-                      </node>
+                    <node concept="1rXfSq" id="17a3YpB4ew" role="33vP2m">
+                      <ref role="37wK5l" node="17a3YpxfeA" resolve="getViewport" />
                     </node>
                   </node>
                 </node>
@@ -9138,17 +9257,26 @@
                     <node concept="3uibUv" id="1oWwpQDO4e9" role="1tU5fm">
                       <ref role="3uigEE" to="z60i:~Rectangle" resolve="Rectangle" />
                     </node>
-                    <node concept="2OqwBi" id="1oWwpQDO4ea" role="33vP2m">
-                      <node concept="2OqwBi" id="1oWwpQDO4eb" role="2Oq$k0">
-                        <node concept="37vLTw" id="1oWwpQDO4ec" role="2Oq$k0">
-                          <ref role="3cqZAo" node="1oWwpQDO4e2" resolve="editorComponent" />
+                    <node concept="3K4zz7" id="17a3YpCRY$" role="33vP2m">
+                      <node concept="2OqwBi" id="17a3YpDQBk" role="3K4E3e">
+                        <node concept="37vLTw" id="17a3YpDD7h" role="2Oq$k0">
+                          <ref role="3cqZAo" node="17a3YpB4ev" resolve="viewport" />
                         </node>
-                        <node concept="liA8E" id="1oWwpQDO4ed" role="2OqNvi">
-                          <ref role="37wK5l" to="exr9:~EditorComponent.getViewport()" resolve="getViewport" />
+                        <node concept="liA8E" id="17a3YpE5h5" role="2OqNvi">
+                          <ref role="37wK5l" to="dxuu:~JViewport.getViewRect()" resolve="getViewRect" />
                         </node>
                       </node>
-                      <node concept="liA8E" id="1oWwpQDO4ee" role="2OqNvi">
-                        <ref role="37wK5l" to="dxuu:~JViewport.getViewRect()" resolve="getViewRect" />
+                      <node concept="2ShNRf" id="17a3YpEo6u" role="3K4GZi">
+                        <node concept="1pGfFk" id="17a3YpFbsA" role="2ShVmc">
+                          <property role="373rjd" value="true" />
+                          <ref role="37wK5l" to="z60i:~Rectangle.&lt;init&gt;()" resolve="Rectangle" />
+                        </node>
+                      </node>
+                      <node concept="3y3z36" id="17a3YpCtUI" role="3K4Cdx">
+                        <node concept="10Nm6u" id="17a3YpCFXi" role="3uHU7w" />
+                        <node concept="37vLTw" id="17a3YpCghJ" role="3uHU7B">
+                          <ref role="3cqZAo" node="17a3YpB4ev" resolve="viewport" />
+                        </node>
                       </node>
                     </node>
                   </node>