Hmm... cannot confirm that observation.
System: Athlon64 3400 / 1G / WinXP SP2 /c::b 1.0finalbeta
2 Projects loaded, 6 files open, all plugins loaded, no Debugger, idle:
Total CPU 2%,
taskmgr.exe 1% <--- that's where my cpu goes
svchost.exe 1% <---
codeblocks.exe 0%
same, but moving Mouse up and down over project manager:
codeblocks.exe 18% (quite clear why that has to be)
frenzily moving Mouse over editor window:
codeblocks.exe 24% (quite clear, too)
compiling project:
cc1.exe 99% (well, duh :-) )
debugging app that is blocking in a syscall (getchar):
codeblocks.exe 0%
app.exe 0%
debugging app that runs in a tight infinite loop with a watch:
codeblocks.exe 5%
app.exe 95%
This looks quite normal to me, does it not?
EDIT:
Forgot about the "moving mouse thing":
Moving the mouse fires a lot of events and requires calculations like "do tooltips have to be popped up?" and "do I need to change a button's outline?" or "is some plugin maybe involved?", so quite clearly this takes cpu.
I can get Windows Explorer to use 3-4% cpu by moving the mouse, too, and Explorer does quite a lot less than an IDE.