Magic Mouse and Trackpad losing clicks

[nOw2]

I have:

• A Magic Mouse on a MBP
• A Magic Mouse on an iMac
• A Magic Trackpad on the same iMac

All three input devices on both computers have the same problem: every few minutes, especially if its been unused for while, a click will not respond. The pointer moves fine on screen, but a left or right click has no effect on the computer. If I click a second time then that second click will always work.

It began happening around the start of this year.

I'm using a USB Microsoft mouse on the MBP without any problems.

This is happening to two separate, unlinked computers (one is at home, the other at work). I believe the only common non-standard item may be MagicPrefs. The Magic Mouse is unusable without this and it hasn't been updated recently.

Has anyone any suggestions at all?