Photoshop :: Action Dialogue Box Not Opening Automatically

I recently upgraded from CS4 to CS5.  I imported some of the actions I had created without problem.
 
I use one for sharpening with the following steps:
 
1. Convert to Lab Mode
2. Select Lightness Channel
3. Open Unsharp Mask Dialogue Box
4. Convert back to RGB Mode
 
The "Dialogue" box is correctly toggled to "on" in Step # 3
 
However when I execute the Action, the Dialogue Box for USM doesn't automatically pop up, as it did in CS4 - but if I click anywhere on the screen, it then does.
 
I tried recreating the same action in CS5, but it has the same problem - the Dialogue Box for USM doesn't open by itself, and only does so after I click anywhere on the screen.
 
This happens both on my Windows Vista Home Premium 64-bit Desktop, and a new Windows 7 Home Premium 64-bit Laptop.

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