Why cant I preview files other than jpeg,jpg,png etc in the list view?

Summary:

Hello,

I have just noticed the following behavior:

When I view canddiate attachments in the list view, I am able to preview only the jpeg,jpg,png files. But not the other file types like pdf, docx, ptt, xlcx etc.

Content (please ensure you mask any confidential information):

• Why cant I preview all attachments in the list view? Why do I have to switch to the preview mode to view some of them?
• Is there a logic behind this? It cant be the file size, as the .png is larger than the .docx in this case here.
• Do I have to change a profile option to activate this feature? Or is this something that is just not possible to do?