All of a sudden, I can no longer add any plugins to any channel strips? And when I click on an existing plugin to edit, it disappears off the channel strip?

I am running Logic express 9 on a 2008 Macbook, (non pro). Anyhow, logic has always seemed to work great for me. However, last week I opened up one of many existing projects, (I'm in sample editor). When I went to add a new plugin to one of the channel strips it would not allow me to. Also, if I click on any plugin that already exists on the channel strip it dissapears? The strange thing that also happens weather I click to add a new plugin or click on an already existing plugin, is both the "repeat section" and "crop", buttons from the above menu (in sample editor), the actual buttons become a faded image,(as far as the actual font and images of the buttons). As soon as I am done clicking to add a plugin on the channel strip, both buttons from the menu go back to looking normal like all of the other choices from that menu? I really don't get it? All I want to do is to be able to add plugins as well as edit or change plugins again. Any thoughts as to why I can no longer add any new plugins to any channel strips? And why any existing plugins disappear from the channel strip when I click on it? Why the "repeat section", and "Crop", buttons from the menu above fade in and out when I try clicking on the channel strip is very strange? I don't mind that I just want to be able to add or edit plugins again. I did do some document cleaning up last week as my memory was getting low. I then emptied out my trash bin. I'm hoping I didn't accidentally delete some kind of Logic component? Why can't I add or edit plugins anymore? Anyone ever run across this?

Thanks,

Mike.