MonoDevelop keeps switching to .Net 3.5

Hi everyone,

When embedding the Facebook SDK / plugin, we got many errors when tried to compile and eventually we discovered that we need to compile all libraries using .Net 4.0

This indeed solved our problems, but every now and then after changing our code (any of the code), we get all the errors back and as you guessed - .Net 3.5 is back. At this point we are forced to revisit all of the Assembly projects settings to set the build option back to .Net 4.0 - quite annoying after the third time :)

Is there any way around this and what might be the cause?

Thanks