Noticed that this one was posted before, though it didn't really get any attention: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=9455&highlight=disconnect [sidefx.com]

Same problem I'm having in 9.0.733 (under XP, if that makes a difference).
Right clicking on connections doesn't bring up the usually menu with the “disconnect” option inside VEX. Actually, not in SHOPs either, for that matter.
Right now, the only way I'm capable of removing any connections in vex is to select a node, right click on a connection, and locate the “remove selected node inputs” option (strange that I can only get this node-centric menu when right clicking on a connection, but not when right-clicking on a node… :? ).
Why that's a completely unacceptable solution: Imagine that I have a node with 20 inputs, and I only want to disconnect one of them.

What are your interface settings set to? You using Compact? Do you have HOUDINI_UISCALE set?

On Houdini 9.0.731 on XP and sometimes it works perfectly…. I slightly change the zoom level and it no longer works.

Yeah, I'm in compact mode. But don't have any HOUDINI_UISCALE global. Should I?

I'm starting to notice that with the zoom though. There is some scale level that it seems to work with (though your placement of the cursor over the connection has to be perfect). I can't delete the connection at any other zoom level.