I have arch with KDE plasma on my laptop. Yesterday I tried a second vga screen using a hdmi-vga adaptor (my laptop has only hdmi entry). Everything worked fine, I used the second screen as an extension of the left border of the main one. I then unplugged the cable and turned off my laptop. Today this is the situation after booting:
The black area is not accessible with the pointer or keyboard.
I can't access the settings or do anything else via desktop environment and I don't know how to move in this way with tty.
Is there a way to reset this behavior?
More info: laptop resolution 1920x1080, Secondary screen resolution 1600x1200. I'm now at the library without possibility to attach anything via hdmi...
UPDATE1: I tried to reboot several times, deleted ~/.kde4 folder, restarted plasmashell, reset to default screen settings (using the few pixels available on the screen). Nothing changed.
UPDATE2: Plugging in the hdmi cable (even without monitor) the problem disappears. When I unplug it comes back. No progress so far. Logging in as root does not show this behavior.
A solution would be resetting your user's KDE modifications to defaults, to do so open a terminal and type
mv ~/.kde ~/.kde.old
Log off, then log in with the same user. The ~/.kde folder and KDE settings will de recreated to default.