IDA speed problem analysis

[Andrew de Quincey]

Hi, I've been doing some more work on this, and I think I've found the culprit 
(my apologies to everyone for the crap I've been talking recently).

Whenever IDA opens the Save box.. and in fact when it does a lot of 
operations, it seems to completely regenerate its menus. It uses an MDI 
interface, and so uses the WM_MDISETMENU message to set menus.

The problem function is controls/menu.c/SetMenu(). Specifically, the call to 
SetWindowPos() passing the SWP_FRAMECHANGED flag. If I comment this call out, 
IDA becomes very fast... as fast as is it in windows. If I add in Y copies of 
that call, IDA becomes about Y times slower.

Looking at the docs on MSDN for WM_MDISETMENU, it says "After sending this 
message, an application must call the DrawMenuBar function to update the menu 
bar". Which implies that the application is in charge of telling the menu bar 
to redraw, meaning the call to SetWindowPos() is superfluous.

However, SetMenu() is used non by MDI menus as well, which DO expect the menu 
to be updated automatically (MSDN: "The window is redrawn to reflect the menu 
change"), which means it can't just be removed.

Does anyone have any suggestions for the cleanest way to resolve this? Perhaps 
MDI should have an internal copy of SetMenu() tailored to its needs? 

BTW, under windows, the MDI code does not call the USER32.SetMenu() function.