I've just started playing Kerbal again and I only have mechjeb 2.9.2 installed as a mod.
When I try and select the landing site, the reticle doesn't appear. All I can do with the mouse is the normal things (rotate, zoom, etc.).
I vaguely remember a simple fix for this and did it awhile ago. Now that I've updated it's occured again and I don't remember the fix.
I running on a Alienware 17R with windows.