Clipper: Fixed an issue where passing an out of bound index to IncludeItemByIndex() could incorrectly offset the final cursor.

One case where it would manifest was calling Combo() with an out of range index. (#8450)

Author: ocornut

docs/CHANGELOG.txt

@@ -103,6 +103,9 @@ Other changes:
   (#8451, #7660) [@achabense]
 - TextLinkOpenURL(): fixed default Win32 io.PlatformOpenInShellFn handler to
   handle UTF-8 regardless of system regional settings. (#7660) [@achabense]
+- Clipper: Fixed an issue where passing an out of bound index to IncludeItemByIndex()
+  could incorrectly offset the final cursor, even if that index was not iterated through.
+  One case where it would manifest was calling Combo() with an out of range index. (#8450)
 - Debug Tools: Added io.ConfigDebugHighlightIdConflictsShowItemPicker (defaults to true)
   to allow disabled Item Picker suggestion in user facing builds. (#7961, #7669)
 - Misc: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursors

imgui.cpp

@@ -3258,11 +3258,11 @@ static bool ImGuiListClipper_StepInternal(ImGuiListClipper* clipper)
     {
         clipper->DisplayStart = ImMax(data->Ranges[data->StepNo].Min, already_submitted);
         clipper->DisplayEnd = ImMin(data->Ranges[data->StepNo].Max, clipper->ItemsCount);
-        if (clipper->DisplayStart > already_submitted) //-V1051
-            clipper->SeekCursorForItem(clipper->DisplayStart);
         data->StepNo++;
-        if (clipper->DisplayStart == clipper->DisplayEnd && data->StepNo < data->Ranges.Size)
+        if (clipper->DisplayStart >= clipper->DisplayEnd)
             continue;
+        if (clipper->DisplayStart > already_submitted)
+            clipper->SeekCursorForItem(clipper->DisplayStart);
         return true;
     }
 
@@ -3279,7 +3279,7 @@ bool ImGuiListClipper::Step()
     ImGuiContext& g = *Ctx;
     bool need_items_height = (ItemsHeight <= 0.0f);
     bool ret = ImGuiListClipper_StepInternal(this);
-    if (ret && (DisplayStart == DisplayEnd))
+    if (ret && (DisplayStart >= DisplayEnd))
         ret = false;
     if (g.CurrentTable && g.CurrentTable->IsUnfrozenRows == false)
         IMGUI_DEBUG_LOG_CLIPPER("Clipper: Step(): inside frozen table row.\n");