Mac: In debugging, can't show dissemble instructions file.

Steps:
1. Load a qt gui application, Set breakpoint at the first line of main function in main.cpp file.
2. Build the project in desktop debug mode, then start debugging.
3. The debug process will stopped at the breakpoint in main function.
4. At this time, Click "Operate by instruction" menu item from "Debug" menu.

Expected:
The dissemble instructions file of main.cpp shows in the editor window.

Actually result:
Nothing happens.