how to change left mouse button popup-menue

[Ekkard Gerlach]

Hi, 

using xfce-3.8.16-1

how can I change left mouse button popup-menue ?
I'd like to delete some default commands and
append my own ones. I'd like to change the commands
on the first level, not in other levels/cascades
like in user menue. I get angry because of lost 
of time while going to user menue first an then 
go to the specific command I want to execute. 

some ideas? 

thx
Ekkard