Full screen not working

In DEVONagent version 3.9.1 on Yosemite 10.10.4 if I am playing a video whenever I click on the double-headed arrow or click Menu View>Enter Full Screen I am not going to Full Screen; in the latter case the whole window goes full screen but the video stays in proportion. This behaviour is not replicated in Chrome where the video does go to Full Screen. Any ideas to rectify this would be appreciated.

Is this a Flash video? The public WebKit framework of Mac OS X is not compatible to this plug-in and its fullscreen mode. HTML 5 videos might support fullscreen viewing (after entering fullscreen window mode).

Well, it’s not officially supported by the WebKit framework but the next maintenance release will support this.

Flash videos seem to work fine, the particular one I am looking at is an MP4: d2pq0u4uni88oo.cloudfront.net/p … 4_high.mp4