Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_opengl3.cpp
#	imgui.cpp

imgui.cpp

@@ -402,6 +402,7 @@ IMPLEMENTING SUPPORT for ImGuiBackendFlags_RendererHasTextures:
                             you may use GetMainViewport()->Pos to offset hard-coded positions, e.g. SetNextWindowPos(GetMainViewport()->Pos)
                           - likewise io.MousePos and GetMousePos() will use OS coordinates.
                             If you query mouse positions to interact with non-imgui coordinates you will need to offset them, e.g. subtract GetWindowViewport()->Pos.
+ - 2026/06/02 (1.92.9) - TreeNode: commented out legacy name ImGuiTreeNodeFlags_SpanTextWidth which was obsoleted in 1.90.7 (May 2024). Use ImGuiTreeNodeFlags_SpanLabelWidth instead.
  - 2026/05/07 (1.92.8) - DrawList: swapped the last two arguments of AddRect(), AddPolyline(), PathStroke().
                          - Before: void ImDrawList::AddRect(ImVec2 p_min, ImVec2 p_max, ImU32 col, float rounding = 0.0f, ImDrawFlags flags = 0, float thickness = 1.0f);
                          - After:  void ImDrawList::AddRect(ImVec2 p_min, ImVec2 p_max, ImU32 col, float rounding = 0.0f, float thickness = 1.0f, ImDrawFlags flags = 0);
@@ -4574,7 +4575,7 @@ void ImGui::Shutdown()
     for (ImFontAtlas* atlas : g.FontAtlases)
     {
         UnregisterFontAtlas(atlas);
-        if (atlas->RefCount == 0)
+        if (atlas->RefCount == 0 && atlas->OwnerContext == &g)
         {
             atlas->Locked = false;
             IM_DELETE(atlas);
@@ -6454,11 +6455,9 @@ ImVec2 ImGui::CalcTextSize(const char* text, const char* text_end, bool hide_tex
     ImVec2 text_size = font->CalcTextSizeA(font_size, FLT_MAX, wrap_width, text, text_display_end, NULL);
 
     // Round
-    // FIXME: This has been here since Dec 2015 (7b0bf230) but down the line we want this out.
-    // FIXME: Investigate using ceilf or e.g.
-    // - https://git.musl-libc.org/cgit/musl/tree/src/math/ceilf.c
-    // - https://embarkstudios.github.io/rust-gpu/api/src/libm/math/ceilf.rs.html
-    text_size.x = IM_TRUNC(text_size.x + 0.99999f);
+    // (see 7b0bf230, 4622fa4b6, #791 for details about this.)
+    // FIXME: Add a way to disable this.
+    text_size.x = ImCeilFast(text_size.x);
 
     return text_size;
 }