Tables: fixed SetNextWindowScroll() value being ignored by BeginTable() during the first frame or when scrolling flags have changed. (#8196)

docs/CHANGELOG.txt

@@ -56,6 +56,8 @@ Other changes:
 
 - Error Handling: fixed cases where recoverable error handling would crash when 
   processing errors outside of the NewFrame()..EndFrame() scope. (#1651)
+- Tables: fixed SetNextWindowScroll() value being ignored by BeginTable() during
+  the first frame or when scrolling flags have changed. (#8196)
 - Misc: changed embedded ProggyClean encoding to save a bit of binary space (~12kb to 9.5kb).
 - Misc: added IMGUI_DISABLE_DEFAULT_FONT to strip embedded font from binary. (#8161)
   [@demonese]

imgui_tables.cpp

@@ -410,7 +410,8 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
 
         // Reset scroll if we are reactivating it
         if ((previous_flags & (ImGuiTableFlags_ScrollX | ImGuiTableFlags_ScrollY)) == 0)
-            SetNextWindowScroll(ImVec2(0.0f, 0.0f));
+            if ((g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasScroll) == 0)
+                SetNextWindowScroll(ImVec2(0.0f, 0.0f));
 
         // Create scrolling region (without border and zero window padding)
         ImGuiWindowFlags child_window_flags = (flags & ImGuiTableFlags_ScrollX) ? ImGuiWindowFlags_HorizontalScrollbar : ImGuiWindowFlags_None;