Inkscape version: 0.91 r13725
OS: Arch Linux
Display server: X
Window manager: i3
When panning by holding space and moving the mouse, Inkscape gets stuck in pan mode. No keypress does anything at this point, and the only way to disable panning is to change workspaces. This happens irregardless of window mode (ie. floating or tiling). When the pan mode is stuck, if I stop moving the mouse and press any mouse button, the pointer changes to that of the tool that was active before panning, but reverts back to pan after moving mouse (and pan is still stuck). When changing workspaces back and forth to escape the pan mode, the pointer is still pan pointer, but reverts back to the tool that was previously used after moving the mouse.
Additional info: After a brief discussion on irc, I was instructed to test if the same thing happens in GIMP. It did not - panning with space works fine in GIMP.
Just reproduced a stuck panning case accidentally on Crunchbang Waldorf, Inkscape 0.91.x rev. 13731, by pressing Space and Tab simultaneously. Not sure it's exactly the same bug though (I'd rather see an issue with the windows manager).