Why Action.MoveUp/MoveDown commands in VS2010 disabled?

The 开发者_如何学GoVS2010 Power Tools provide functions to move lines up/down but I found these have stopped working. No amount of fiddling, reinstalling Power Tools, rebinding keystrokes, etc. has got them working again. Only after adding the Action.MoveUp and Action.MoveDown commands to my Edit | Advanced menu, where I thought I had seen them before, do I see that they are disabled.

What might disable these? How can I re-enable them?

I haven't figured out how to fix the individual problem but have done so by resetting my VS2010 settings to default.