No preview with the plugin "Redmine All Thumbnails" & "Redmine Preview Office"

[double2ugly]

Hi,
the preview is not possible when clicking on a thumbnail of a non pic or pdf format (i.e. office-file etc.).
In the previous version the user was asked to open or save the file.
Now the following error-message appears in the preview...:
"The requested content cannot be loaded. Please try again later."
Probably this occurs due to the fact that the Preview Office plugin generates a pdf-file in the first place...

I'm running Redmine v4.0.2

[tofi86]

As I'm pretty busy at the moment, I cannot add support for new plugins. If someone can send a PR this would be very well appreciated! :-)