diff --git a/3rdparty/dear-imgui/imgui.cpp b/3rdparty/dear-imgui/imgui.cpp
index d33d3d8a3..22aa5aff2 100644
--- a/3rdparty/dear-imgui/imgui.cpp
+++ b/3rdparty/dear-imgui/imgui.cpp
@@ -7935,10 +7935,10 @@ static void ImGui::NavUpdate()
         g.IO.NavInputsDownDuration[i] = (g.IO.NavInputs[i] > 0.0f) ? (g.IO.NavInputsDownDuration[i] < 0.0f ? 0.0f : g.IO.NavInputsDownDuration[i] + g.IO.DeltaTime) : -1.0f;
 
     // Process navigation init request (select first/default focus)
-    if (g.NavInitResultId != 0 && (!g.NavDisableHighlight || g.NavInitRequestFromMove))
+    // In very rare cases g.NavWindow may be null (e.g. clearing focus after requesting an init request, which does happen when releasing Alt while clicking on void)
+    if (g.NavInitResultId != 0 && (!g.NavDisableHighlight || g.NavInitRequestFromMove) && g.NavWindow)
     {
         // Apply result from previous navigation init request (will typically select the first item, unless SetItemDefaultFocus() has been called)
-        IM_ASSERT(g.NavWindow);
         if (g.NavInitRequestFromMove)
             SetNavIDWithRectRel(g.NavInitResultId, g.NavLayer, g.NavInitResultRectRel);
         else
diff --git a/3rdparty/dear-imgui/imgui_widgets.cpp b/3rdparty/dear-imgui/imgui_widgets.cpp
index b55263827..cf2bbcd66 100644
--- a/3rdparty/dear-imgui/imgui_widgets.cpp
+++ b/3rdparty/dear-imgui/imgui_widgets.cpp
@@ -1411,7 +1411,7 @@ bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboF
     const float value_x2 = ImMax(frame_bb.Min.x, frame_bb.Max.x - arrow_size);
     RenderNavHighlight(frame_bb, id);
     if (!(flags & ImGuiComboFlags_NoPreview))
-        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(value_x2, frame_bb.Max.y), frame_col, style.FrameRounding, ImDrawCornerFlags_Left);
+        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(value_x2, frame_bb.Max.y), frame_col, style.FrameRounding, (flags & ImGuiComboFlags_NoArrowButton) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Left);
     if (!(flags & ImGuiComboFlags_NoArrowButton))
     {
         window->DrawList->AddRectFilled(ImVec2(value_x2, frame_bb.Min.y), frame_bb.Max, GetColorU32((popup_open || hovered) ? ImGuiCol_ButtonHovered : ImGuiCol_Button), style.FrameRounding, (w <= arrow_size) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Right);