Please describe the problem:
If you set Ctrl+PgUp/Ctrl+PgDn for switching to previous/next tab, but you have just one tab (e.g. just the main window), Ctrl+PgUp works in the terminal, but Ctrl+PgDn doesn't. In fact, I'm seldom using multiple tabs but losing Ctrl+PgDn is quite uncomfortable as I'm used to it in editors (and it worked in 2.20).


Steps to reproduce:
1. Set Ctrl+PgUp/Ctrl+PgDn as the combinations to switch to next/prev tab.
2. Open a large text file in some editor that uses Ctrl+PgUp/Ctrl+PgDn to move the cursor (I'm using mcedit which goes to beginning/end of file)
3. Go to the middle of the file with PgDn
4. Press Ctrl+PgUp, it will go to beginning of the file
5. Press Ctrl+PgDn, this does nothing


Actual results:


Expected results:


Does this happen every time?
Yes

Other information:
I understand that setting Ctrl+PgDn as a hotkey and wanting to use it in terminal at the same time is asking for troubles; however, the behaviour of Ctrl+PgUp and Ctrl+PgDn is at least inconsistent. They should either both not work, or both work when just one tab is in use (I'd prefer the later ;)