fix: Calling [NSCurser set] unconditionally is expensive

Author: stuartcarnie

backends/imgui_impl_osx.mm

@@ -96,13 +96,13 @@ - (void)keyDown:(NSEvent *)event {
 - (void)insertText:(id)aString replacementRange:(NSRange)replacementRange
 {
     ImGuiIO& io = ImGui::GetIO();
-    
+
     NSString *characters;
     if ([aString isKindOfClass:[NSAttributedString class]])
         characters = [aString string];
     else
         characters = (NSString *)aString;
-    
+
     io.AddInputCharactersUTF8(characters.UTF8String);
 }
 
@@ -271,7 +271,7 @@ bool ImGui_ImplOSX_Init(NSView *view)
                                              selector:@selector(onApplicationBecomeInactive:)
                                                  name:NSApplicationDidResignActiveNotification
                                                object:nil];
-    
+
     g_KeyEventResponder = [[KeyEventResponder alloc] initWithFrame:NSZeroRect];
     [view addSubview:g_KeyEventResponder];
 
@@ -309,8 +309,13 @@ static void ImGui_ImplOSX_UpdateMouseCursorAndButtons()
     }
     else
     {
+        NSCursor *desired = g_MouseCursors[imgui_cursor] ?: g_MouseCursors[ImGuiMouseCursor_Arrow];
         // Show OS mouse cursor
-        [g_MouseCursors[g_MouseCursors[imgui_cursor] ? imgui_cursor : ImGuiMouseCursor_Arrow] set];
+        if (desired != NSCursor.currentCursor)
+        {
+            [desired set];
+        }
+        // [g_MouseCursors[g_MouseCursors[imgui_cursor] ? imgui_cursor : ImGuiMouseCursor_Arrow] set];
         if (g_MouseCursorHidden)
         {
             g_MouseCursorHidden = false;