Different commands according to mouse button.

If you use that syntax:
%{A:command 1:command 2:}Text%{A}
"command 1" will be executed if you use left click
"command 2" will be executed if you use right click

%{A:command:}Text%{A} still behave normally (executed on left click).

The new syntax (%{A<button>:command:}) is broken with that commit.