Adobe Encore button issues

Hi,

I have been an avid user of Adobe Encore for a while now, as we use it here at my workplace, but I've seem to run into an issue that I've never had before and can't seem to find a solution for.

The problem is is that have the buttons refuse to be selected. It will only select 18 out of the 31 on the menu. I have never run into this issue before with making a bluray. I've heard that there is a limit on how many buttons can be on one page I believe it is a spec limit or something along those lines. However I have never had this issue before. Could someone shed some light on this for me please?