From 8db02ef8df45381117f5b7271e68aee43e17e414 Mon Sep 17 00:00:00 2001
From: ocornut <omarcornut@gmail.com>
Date: Mon, 16 Oct 2023 21:33:51 +0200
Subject: [PATCH] Tables: Fixed an issue with ScrollX enabled where an
 extraneous draw command would be created.

Randomly found while deep-diving into #6765.
ContentMaxXHeadersUsed has been set to max since the dawn of tables, which contradict the intent of passing zero-width to ItemSize(). The ItemSize code allowed SameLine() to operate, but this mistake setting ContentMaxXHeadersUsed would make right-most visible column in a ScrollX set incorrectly use a draw command due to header claiming whole column width.
---
 docs/CHANGELOG.txt | 3 ++-
 imgui_tables.cpp   | 7 +++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index d8060abaf9a6..2f8ef3d0d7c5 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -109,7 +109,8 @@ Other changes:
   - Fixed bottom-most and right-most outer border offset by one. (#6765, #3752) [@v-ein]
   - Fixed top-most outer border being drawn with both TableBorderLight and TableBorderStrong
     in some situations, causing the earlier to be visible underneath when alpha is not 1.0f.
-  - fixed right-clicking right-most section (past right-most column) from highlighting a column.
+  - Fixed right-clicking right-most section (past right-most column) from highlighting a column.
+  - Fixed an issue with ScrollX enabled where an extraneous draw command would be created.
 - TabBar: Fixed position of unsaved document marker (ImGuiTabItemFlags_UnsavedDocument) which was
   accidentally offset in 1.89.9. (#6862) [@alektron]
 - Fonts: 'float size_pixels' passed to AddFontXXX() functions is now rounded to lowest integer.
diff --git a/imgui_tables.cpp b/imgui_tables.cpp
index e028376d537d..fac9b05f5ae7 100644
--- a/imgui_tables.cpp
+++ b/imgui_tables.cpp
@@ -3015,11 +3015,14 @@ void ImGui::TableHeader(const char* label)
     // Calculate ideal size for sort order arrow
     float w_arrow = 0.0f;
     float w_sort_text = 0.0f;
+    bool sort_arrow = false;
     char sort_order_suf[4] = "";
     const float ARROW_SCALE = 0.65f;
     if ((table->Flags & ImGuiTableFlags_Sortable) && !(column->Flags & ImGuiTableColumnFlags_NoSort))
     {
         w_arrow = ImTrunc(g.FontSize * ARROW_SCALE + g.Style.FramePadding.x);
+        if (column->SortOrder != -1)
+            sort_arrow = true;
         if (column->SortOrder > 0)
         {
             ImFormatString(sort_order_suf, IM_ARRAYSIZE(sort_order_suf), "%d", column->SortOrder + 1);
@@ -3027,9 +3030,9 @@ void ImGui::TableHeader(const char* label)
         }
     }
 
-    // We feed our unclipped width to the column without writing on CursorMaxPos, so that column is still considering for merging.
+    // We feed our unclipped width to the column without writing on CursorMaxPos, so that column is still considered for merging.
     float max_pos_x = label_pos.x + label_size.x + w_sort_text + w_arrow;
-    column->ContentMaxXHeadersUsed = ImMax(column->ContentMaxXHeadersUsed, column->WorkMaxX);
+    column->ContentMaxXHeadersUsed = ImMax(column->ContentMaxXHeadersUsed, sort_arrow ? cell_r.Max.x : ImMin(max_pos_x, cell_r.Max.x));
     column->ContentMaxXHeadersIdeal = ImMax(column->ContentMaxXHeadersIdeal, max_pos_x);
 
     // Keep header highlighted when context menu is open.