Taskbar Preview Thumbnail glitch

[roebuck]

Hello All,

I am having a problem with the taskbar preview thumbnails and app preview. It seems that the thumbnail previews are regularly "forgotten", such that if I hover over a taskbar button, I get a sort of generic blank thumbnail that doesn't reflect the content of the running app. If I then hover over the thumbnail, I get a blank generic window instead of an actual preview of the app.

If I restore the app window and minimize again, the thumbnail/preview feature works as it ought to, but after some length of time or circumstances I can't see a pattern to, it reverts back to the above-described behavior.

And yes, I do have "save taskbar thumbnail previews" checked in Performance Options.

Does anyone else experience this glitch, and/or know of a fix?

TIA...

roebuck

[Yochanan]

You can try clearing the thumbnail cache by running Disk Cleanup and selecting Thumbnails.

[nautiqueskier]

The thumbnail cache is not used for the window previews

The way I understand it, the window previews are actual renders of the application and are stored in the DWM buffer (they don't exist as files on the disk)

When applications are minimized Windows is unable to generate a thumbnail (because of the way Windows is designed, minimized applications don't actually draw a UI, in order to increase performance). Because of this, minimized applications use the last rendered thumbnail from the buffer. But if anything causes Windows to lose the thumbnails, it won't be able to recreate them until the application is restored.

Because the thumbnails are stored in the DWM buffer if Aero is disabled, all the thumbnails are lost (for example if you run a game). Windows will not be able to regenerate those thumbnails until the applications are no longer minimized. Also, I believe Windows releases the thumbnails to free up video memory if required which is why thumbnails occasionally disappear.

So its not really a glitch but more of a limitation of the design.

Hope this helps.

[roebuck]

Thanks for the replies folks!

Yes, I figured out that when I fired up my ancient Quicken, which I've set up to run with compositing off, the thumbnails were forgotten. Ditto Stellarium, which starts up in a fullscreen mode.

Guess I'll just have to roll with it.

- roebuck

The thumbnail cache is not used for the window previews

The way I understand it, the window previews are actual renders of the application and are stored in the DWM buffer (they don't exist as files on the disk)

When applications are minimized Windows is unable to generate a thumbnail (because of the way Windows is designed, minimized applications don't actually draw a UI, in order to increase performance). Because of this, minimized applications use the last rendered thumbnail from the buffer. But if anything causes Windows to lose the thumbnails, it won't be able to recreate them until the application is restored.

Because the thumbnails are stored in the DWM buffer if Aero is disabled, all the thumbnails are lost (for example if you run a game). Windows will not be able to regenerate those thumbnails until the applications are no longer minimized. Also, I believe Windows releases the thumbnails to free up video memory if required which is why thumbnails occasionally disappear.

So its not really a glitch but more of a limitation of the design.

Hope this helps.

[bogas04]

so is there any fix?

[MarkusDarkus]

The thumbnail cache is not used for the window previews

The way I understand it, the window previews are actual renders of the application and are stored in the DWM buffer (they don't exist as files on the disk)

When applications are minimized Windows is unable to generate a thumbnail (because of the way Windows is designed, minimized applications don't actually draw a UI, in order to increase performance). Because of this, minimized applications use the last rendered thumbnail from the buffer. But if anything causes Windows to lose the thumbnails, it won't be able to recreate them until the application is restored.

Because the thumbnails are stored in the DWM buffer if Aero is disabled, all the thumbnails are lost (for example if you run a game). Windows will not be able to regenerate those thumbnails until the applications are no longer minimized. Also, I believe Windows releases the thumbnails to free up video memory if required which is why thumbnails occasionally disappear.

So its not really a glitch but more of a limitation of the design.

Hope this helps.

Hmm Interesting. I always wondered why that happened.