To reproduce:
Open up a new document, and open up Task Manager or some similar monitoring software. Leave Task Manager somewhere such that you can see CPU usage even when the monitor isn't the active window.
Create a new layer underneath the current layer.
Hide the new layer.
Undo (Ctrl Z).
Redo (Ctrl Y), and don't move your mouse cursor.
Note that CPU usage will jump to max (which is 25-30% on my machine).
Reproduced on 0.91pre2 64 bit (except not really, it's a more recent revision) on Windows 8.1.
Not reproduced on 0.48.4 on Ubuntu in VMWare.
To reproduce:
Open up a new document, and open up Task Manager or some similar monitoring software. Leave Task Manager somewhere such that you can see CPU usage even when the monitor isn't the active window.
Create a new layer underneath the current layer.
Hide the new layer.
Undo (Ctrl Z).
Redo (Ctrl Y), and don't move your mouse cursor.
Note that CPU usage will jump to max (which is 25-30% on my machine).
Reproduced on 0.91pre2 64 bit (except not really, it's a more recent revision) on Windows 8.1.
Not reproduced on 0.48.4 on Ubuntu in VMWare.