On most boots, I have 2 or 3 displays connected out of 4 normally available. It is unusual when more than one are same resolution as others. The only matched pair are 1680x1050. Most commonly it is 2560x1440 or 1920x1200 as primary, and 1680x1050 as other, or 2560x1440 as primary, and 1920x1200 and 1680x1050 as other. I keep an xrandr miniscript, in e.g. in Debian and *buntu /etc/X11/Xsession.d/, for the purpose of having the positions and primary as I usually want them with the particular PC involved, as among the PCs, available GPU outputs vary in number and type. On any given boot, I may either connect them differently, or want different positions than usual.

Bug?: I cannot remember a time when the behavior was any better than now. When I run xrandr to make a change that should result in Kicker moving to a different display, it generally gets the resulting position wrong, sometimes above the (expected) bottom, sometimes misplaced horizontally. The only case I remember that it gets it right is if the change moves primary below another display instead of horizontally.

Occurrance just observed resulted from: xrandr --output HDMI-1 --primary --output DVI-I-1 --right-of HDMI-1

This shifted side-by-side's primary as desired from 1680x1050 display to 1920x1200 display. Kicker moved from smaller display to larger, correctly positioned vertically, but off by 1680px horizontally to the right, thus mostly invisible.

Only fix to this I've found without opening arandr or KControl (both of which I rarely open for such a purpose) is to alter the script, log out, and log back in.