Same problem after Ubuntu Gnome 15.04 clean installation. Shortcut "Modifiers-only switch to next source"(allow set combinations like "Shift+Alt") works incorrect. "Switch to next input source" and "Switch to previous input source" works fine, but doesn't allow set combinations like "Shift+Alt" through GUI.
Workaround. Disable "Modifiers-only switch to next source" and manually set "Switch to next input source" and "Switch to previous input source".
gsettings set org.gnome.desktop.input-sources xkb-options "[]"
gsettings set org.gnome.desktop.wm.keybindings switch-input-source "['<Alt>Shift_L']"
gsettings set org.gnome.desktop.wm.keybindings switch-input-source-backward "['<Alt>Shift_R']"
Same problem after Ubuntu Gnome 15.04 clean installation. Shortcut "Modifiers-only switch to next source"(allow set combinations like "Shift+Alt") works incorrect. "Switch to next input source" and "Switch to previous input source" works fine, but doesn't allow set combinations like "Shift+Alt" through GUI.
Workaround. Disable "Modifiers-only switch to next source" and manually set "Switch to next input source" and "Switch to previous input source".
gsettings set org.gnome. desktop. input-sources xkb-options "[]" desktop. wm.keybindings switch-input-source "['<Alt>Shift_L']" desktop. wm.keybindings switch- input-source- backward "['<Alt>Shift_R']"
gsettings set org.gnome.
gsettings set org.gnome.