Combo: Arrow button isn't displayed over frame color, so color is consistent with other button + the button doesn't have inner rounding.

imgui.cpp

@@ -10596,8 +10596,9 @@ bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboF
     const float arrow_size = GetFrameHeight();
     const ImRect value_bb(frame_bb.Min, frame_bb.Max - ImVec2(arrow_size, 0.0f));
     RenderNavHighlight(frame_bb, id);
-    RenderFrame(frame_bb.Min, frame_bb.Max, GetColorU32(ImGuiCol_FrameBg), true, style.FrameRounding);
-    RenderFrame(ImVec2(frame_bb.Max.x-arrow_size, frame_bb.Min.y), frame_bb.Max, GetColorU32(popup_open || hovered ? ImGuiCol_ButtonHovered : ImGuiCol_Button), true, style.FrameRounding); // FIXME-ROUNDING
+    window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Max.y), GetColorU32(ImGuiCol_FrameBg), style.FrameRounding, ImDrawCornerFlags_Left);
+    window->DrawList->AddRectFilled(ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Min.y), frame_bb.Max, GetColorU32(popup_open || hovered ? ImGuiCol_ButtonHovered : ImGuiCol_Button), style.FrameRounding, (w <= arrow_size) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Right);
+    RenderFrameBorder(frame_bb.Min, frame_bb.Max, style.FrameRounding);
     RenderArrow(ImVec2(frame_bb.Max.x - arrow_size + style.FramePadding.y, frame_bb.Min.y + style.FramePadding.y), ImGuiDir_Down);
     if (preview_value != NULL)
         RenderTextClipped(frame_bb.Min + style.FramePadding, value_bb.Max, preview_value, NULL, NULL, ImVec2(0.0f,0.0f));