The following two videos, embedded as thumb:

[[File:The Impact of Wikipedia Ravan Jaafar Altaie.webm|thumb|400px|caption]]
[[File:Roundhay Garden Scene.ogg|thumb|400px|caption]]

The wiki-syntax for them is 100% similar, except the filename (and the file type). One would expect that they behave similarly, however, the first one appears in a popup window upon click, while the 2nd is directly playing the video without opening a popup.

It should either open the video in a popup (dialog) in both or them, or in none of them.