Ignorant keyboard question

["Yo Intl. YK" rrr@xxxxxxxx]

I like to have a key that turns the current line to uppercase. For that
purpose, I put this into the keyboard file:
46=XD,DL,BX,u,c,Q2,CC,XD,CC

In XY4 the problem is, this seems to work only when there is already a line
return; if I use it right after typing the line, it does not work. So, I
have to type return, backspace, and then the shortcut key. Waste of time.
Now, in XY3 the same thing (with BC...XC of course) worked perfectly, no
matter where.
Can somebody tell me what I have to tweak to make this work? (I guess I am
showing my ignorance again... sorry).

Tia


-- Rene von Rentzell