TreeNode: Fixed combination of ImGuiTreeNodeFlags_SpanFullWidth and ImGuiTreeNodeFlags_OpenOnArrow incorrectly locating the arrow hit position to the left of the frame. (#2451, #2438, #1897)

Author: ocornut

docs/CHANGELOG.txt

@@ -38,6 +38,8 @@ Breaking Changes:
 
 Other Changes:
 - InputText, Nav: Fixed Home/End key broken when activating Keyboard Navigation. (#787)
+- TreeNode: Fixed combination of ImGuiTreeNodeFlags_SpanFullWidth and ImGuiTreeNodeFlags_OpenOnArrow
+  incorrectly locating the arrow hit position to the left of the frame. (#2451, #2438, #1897)
 
 
 -----------------------------------------------------------------------

imgui_widgets.cpp

@@ -5270,9 +5270,11 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
     {
         if (pressed)
         {
+            const float arrow_x1 = text_pos.x - text_offset_x;
+            const float arrow_x2 = arrow_x1 + g.FontSize + padding.x * 2.0f;
             toggled = !(flags & (ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick)) || (g.NavActivateId == id);
             if (flags & ImGuiTreeNodeFlags_OpenOnArrow)
-                toggled |= IsMouseHoveringRect(interact_bb.Min, ImVec2(interact_bb.Min.x + text_offset_x, interact_bb.Max.y)) && (!g.NavDisableMouseHover);
+                toggled |= IsMouseHoveringRect(ImVec2(arrow_x1, interact_bb.Min.y), ImVec2(arrow_x2, interact_bb.Max.y)) && (!g.NavDisableMouseHover);
             if (flags & ImGuiTreeNodeFlags_OpenOnDoubleClick)
                 toggled |= g.IO.MouseDoubleClicked[0];
             if (g.DragDropActive && is_open) // When using Drag and Drop "hold to open" we keep the node highlighted after opening, but never close it again.