[SOLVED] Cannot change image tv in random resources (Revo 2.2.6)

My client just noticed that for random resources they cannot change image tv content once the resource has been saved for the first time. For the majority of resources it is working fine but recently some resources no longer display the dropdown to allow editing the tv. Please see attached screenshots of the way it should be and the way it is where there's the problem. In both examples, we're using the same template to create a product page.

Any ideas what might be causing this?? [ed. note: intandem last edited this post 13 years, 7 months ago.]

Any consistencies like only for certain templates? Any js errors happening in the mgr (it sounds like non Image TVs save ok). What if the resource is unpublished then republished? Duplicated?
If you use Chrome dev tools, do you see any requests made when trying to edit a image tv (calling for modal upload window)
All shots in the dark but help debugging.

Just figured out that the client set up some assets/images subfolder names with apostrophes in them and all offending resources are linked to these. So a renaming should sort it all out. Thanks for your suggestions!

Ah. Another caveat to be aware of is, at least last time I checked, phpthumbof does not support spaces in file or folder names.