What version of Premiere Elements are you using and on what computer operating system is it running?
What are the properties of the clip that you are trying to trim? Are you double clicking the file's thumbnail in Project Assets (versions 11 or 12) or Project Media (versions earlier than 11) to open the Preview Windows with the Set In Set Out points?
What workspace are you working in, Expert or Quick (versions 11 or 12) or Timeline or Sceneline (versions earlier than 11)?
Please review the Preview Window details for trimming clips
After you review of the above, we can try to sort through the details to a resolution to the issue that you present.
Thank you. Looking forward to your follow up.
Thanks for your reply. To answer your questions:
I'm using Premiere 12.1 on Windows 7 64 bit
In expert mode I'm double clicking a clip to bring up the preview window. I have checked the two links you provided and they did not answer my question. I can manually select in and out points by sliding the two indicators along the clip, but it's hard to be accurate and is not as fast as clicking the set-in and set-out buttons, which are unresponsive. If I recall correctly, I had the same issue when I had Premiere 11 on my computer. It used to work, then one day stopped working. I thought the issue would be resolved once I upgraded to 12, but that didn't happen. (I say that MAY be the case, because that was awhile ago so I don't remember for sure.)
Thanks for the follow up.
Interesting that you might be experiencing the same Preview Window problem with 12 and 11.
First, are you double clicking the file's thumbnail in Project Assets instead of the file on the Timeline to open the Preview Window?
You mention that you can do Set In and Set Out points manually. Have you tried playing the Timeline and using the shortcuts, I for Set In and O for Set Out? Or are the shortcuts non functional as are the Set In and Set Out tabs of the Preview Window?
Have you gone through the classical deletion of the settings file (Adobe Premiere Elements Prefs) which is frequently effective in these cases of unexpected glitches. To do that
Local Disk C
and in the 12.0 Folder is the Adobe Premiere Elements Prefs file that you delete. If that does not work, then delete the whole 12.0 Folder in which the Adobe Premiere Elements Prefs file exists. Make sure to be working with Folder Option Show Hidden Files, Folders, and Drives active so that you can see the complete path cited.
We will be watching for further developments.