AutoCAD Architecture :: Trim Command Skipping Lines

We recently upgraded to Autocad Architecture 2013 and the trim command is driving me mental. Lets say I have a window mullion pattern with 4 intersecting lines and I want to trim out the center. (see attached example) I start the trim command, then right to left window to select the 4 lines, then use another right to left selection window to trim out the lines. It always leaves on of the lines leaving me to have to click one more time. This is a huge pain when you have to do this multiple times. That is a lot of extra clicks. What gives? I never had this issue before.