Problem A:
Run gdb with -tui option instead (https://bbs.archlinux.org/viewtopic.php?id=112660)
Change your terminal to get rid of your first problem. I used to use gnome-terminal my self, but then changed to terminator. Some terminals don't support keys like Alt sometimes (used to experience this in vim with some Alt+something maps)
You can change forcus to another window by 'focus winName', in your case, use 'focus src' got this from here
Not sure about your 2nd problem. Good luck!
I think you are looking for, "focus next." it switches you among (there can be more than two) the windows. I'm sure there is a short-cut for this too. Please note, this is almost the same answer as user1888039, so if you agree you should up-vote that answer.
~/.inputrc
was the culprit in GDB 7.7 because of:
set editing-mode vi
set keymap vi
If I remove those lines it works.
This seems to be mentioned at in the following bug report: https://sourceware.org/bugzilla/show_bug.cgi?id=15163
I have requested a workaround at https://sourceware.org/ml/gdb/2015-06/msg00009.html and Andrew Burgess replied that he had just submitted a well received patch to add:
tui enable
tui disable
so in future versions we should have commands as an alternative to the shortcuts.
But then I saw the light and moved from TUI to GDB Dashboard: https://github.com/cyrus-and/gdb-dashboard which is simply more powerful and less buggy. See also: How to highlight and color gdb output during interactive debugging?