While trying to create a guideline, the inkscape window gets resized automatically making impossible to create any guideline. This is not a inskcape bug , i'm able to create guidelines in linux using other DEs or Windows, but maybe some Inkscape/KDE4 users may have experienced this problem. I've tried to change some options in "windows behavior" in KDE options but i couldn't fix it . This isn't new, usually when i have to use guidelines i have to switch to other DEs or use a Windows virtual machine, very annoying.

Inkscape 0.91, with kde 4.14

uname -a
Linux arch-itx 4.0.4-2-ARCH #1 SMP PREEMPT Fri May 22 03:05:23 UTC 2015 x86_64 GNU/Linux

Do you use oxygen-gtk as theme-engine/theme for Gtk+ applications? If yes - some workarounds are mentioned in the comments of this bug report:

• Bug #1109812 “Guides not accessible in KDE with oxygen-gtk”

If you don't want to switch to the stock Gtk+ theme (Raleigh), see comment 11 for a tip what to change in the oxygen-specific settings.

Yes, i'm using oxygen-gtk2 and that's the problem. I solved it following post 11 directions. I was looking for some KDE option that could solve it under "windows behavior" settings but the proper setting wasn't there, i have to know better my kde (or maybe kde could put every "windows behavior" option under the same menu setting :p).
Thank you very much man, you even point me to the right comment, thanks. It was a really annoying bug and really easy to solve it if you knew where to look at. I didn't .