https://bugzilla.redhat.com/show_bug.cgi?id=1134299
--- Comment #4 from Mike FABIAN mfabian@redhat.com --- Rui Matos also told me that LeftAlt+RightShift does not switch (only the other 3 combinations mentioned in comment#2 switch).
I tried again and Rui is right.
The reason why I thought that LeftAlt+RigthShift does switch input sources is that switching the input source to “gucharmap” unexpectedly remapped my keyboard layout (probably to “us”). This changed the position of the left alt key (My own layout has the left alt key on the left control key and the left alt key is "Meta" (for use in Emacs)). Switching to the "gucharmap" input source mapped the left alt key to its usual position and the left control key became control again. So it was LeftCtrl+RightShift again doing the input source switching, *not* LeftAlt+RightShift.