Hello,
*I have the same issue. I run some testes to figure out where is problem and I found:
By default uploading videos is turned OFF globally (Setup -> Options -> Attachments -> Allow video uploads with maximum file size ), so that's why the video pop-up windows doesn't show when clicking on the video icon.
*I also played with the groups permissions and found that:
Upload attachments to posts or Upload videos to posts if one of them is set to NO or both the video uploading icon doesn’t hide from the editor toolbar in Threads and Posts.
In Profile Posts, we don't allow attachments to work there so the video uploading icon should be removed.
*In conversations I found the permissions function is broken:
Upload attachments to conversations: doesn't do anything if it is set to NO I can always upload attachments.
Upload videos to conversations: doesn’t hide from the editor toolbar the videos uploading icon when the permission is set to NO.