I just noticed a critical bug in the way IDEA handles CVS updates when Merge with branch has been selected. It basically seems that IDEA doesn't support that functionality if a conflict is generated by the update. First of all, IDEA doesn't detect that there has been a conflict. And secondly, IDEA's internal Merge tool doesn't support fixing that conflict.
The interesting thing is that this problem seems to be both in 4.0 and 4.5 EAPs. To me, this is a very critical issue because it basically renders IDEA useless when used with CVS and branches. I'm just curious how this bug has not come up before - is there something wrong with my configuration or can it really be that nobody is using branches with CVS?
A more detailed description of the bug is available here: http://www.intellij.net/tracker/idea/viewSCR?publicId=36324