[Win7]Beware of a Strange Mutation of the Thumbnail Preview

No preview would be shown and that of the active window can only have its label pop up, no matter how the default settings are changed. Possbile frozen on the hover action(s) and/or clicking action might also appears randomly.

The possible sequence 1/ to trigger the mutation:

1. set the taskbar appearance to "Auto-hide" with the buttons "Never Combine"
2. set the Combine grouped buttons
3. set decombing on mouse hover only
4. sleep/standby and wake the PC

Frozen right click action on the tray icon might also experienced. After 1/ happened, the following behaviours cannot be executed correctly:

Advanced option: mouse control (taskbaritem|lclick) vaule 7

AND

Defines the preview to show when hovering over a taskbar item:
List

such that only list can be triggered but no thumbnail preview was shown at all for combined items. No anymore thumbnail can be triggered if and only if not triggering the "This option doesn't have any effect when the "Combine when taskbar is full" option is chosen in the taskbar properties.".

Possible Preventive Measures

Restart the problematic program before sleep/standby.

Never set taskbar buttons to "Never combin" together with non-default combining/grouping option(s).

Use only default Windows 7 theme before and during 1/.