Cannot delete plugin in control room

Hi , for some time i have been using 2 plugins in the control room for my speakers first is arc 2 and then a limiter psp xeon. ive not used these for a while and now i cannot seem to open or delete them from the insert rack.they seem to stay grey. i checked in the plugins menu and they are active. has anyone got an idea how i can resolve this issue.

thanks
Screen Shot 2013-10-07 at 22.32.24.png

Disable “Constrain delay compensation”

thanks this resolved the issue ,but what was strange is that it was not on . but i turned it on the n off it not i can use the plugins.
thanks again.