Version: (using KDE 4.1.1) Installed from: Ubuntu Packages Konsole uses crtl + pageup/pagedown for tab switching. Irssi uses those to scroll back in the buffer. When you press crtl + pageup/pagedown, Konsole wins out and switches the Konsole tab. Looking at the shortcut menu it looks like crtl + pageup *is* an alternate shortcut, but it's still conflicting.
Yea, Konsole will always grab those shortcuts and doesn't send them to the running app. You're only option is to change the Konsole shortcuts. You should only have to change it once. Reopen this if you think we should remove those 2 shortcuts from the default. I don't think we can simply remove all shortcuts that conflict with some program.