xfce4 shortcuts (mostly) not working with xdotool

I want to make a keyboard shortcuts for automatically entering predefined texts with xdotool. I made a shell script file and want to run it through the keyboard. When i assign shortcut throught xfce4's application shortcuts, most combinations don't work. The only ones that work properly are CTRL, ALT and SHIFT (both L and R works), but when i assign combinations like LCTRL+P, SUPER+ENTER etc.. i doesn't work properly. If i continously press the combinatins that don't work, sometimes(like 10% of the time) it outputs the last one or two letters but never the full text. shell script example: xdotool key m+y+t+e+x+t+KP_Enter it works perfectly when i run it in terminal or with the above mentioned shortcuts but i want to be able to assign combination shortcuts.