This is driving me crazy. I'm not going to take it anymore. I'm going to ask, even at the risk of eternal public humiliation! (If it's something really obvious or that I've done to the system myself).
For reasons I've never quite had the patience to work out, every so often the form I'm working on in Delphi 2007's visual form editor goes 'pseudo-read-only'; I can add new components to the form, I can move/resize existing ones (and change any properties in the Object Inspector), and I can select a component and 'copy' it to the clipboard.
But I'm completely unable to cut a component from the form, or paste a new copy down. I don't believe it's to do with the 'Lock Controls' Edit menu option as I can toggle this on or off and it has the effect it's supposed to - this disappearance of Cut & Paste happens on the right-click context menu, from the keyboard and from the main Edit menu - it's as if the form has become read only to thing to do with the clipboard.
If I close the form in the IDE and then reopen it, everything starts working fine again (just as D1, D3, D5 and D7 always did for me, previously).
I'm not going mad, as I'm sure I read something about why this happens on a newsgroup once and it's caught me out from time to time many many times in the last few months, but I've failed to find the newsgroup reference this evening and I've decided that, as more and more Delphi users seem to be making use of StackOverflow, it was worth asking here.
Help - when I'm doing lots of form-work it drives me absolutely mad!