Quote Originally Posted by Elemenz View Post
Just double right click anything in your bag to move it to the retainer.
You can already do this.
There are two user settings that can prevent it from working.

A) Your inventory window is close to the edge of the screen, which causes the submenu to nudge away from the edge so that it doesn't go off the edge, and the Entrust to Retainer option will not be directly under your cursor.
B) Your submenu has Entrust to Retainer in a lower priority so that it is no longer the topmost option when interacting with your retainer.

You can fix A by moving your inventory window away from the edge of the screen. Fix B by customizing your submenu so that Entrust to Retainer is the highest priority option out of the options that are available when interacting with a retainer. Any options that are available when interacting with the retainer inventory should be below Entrust to Retainer.