Options to stop video when writing/setting annotations are hidden

[dagraf]

Branch: stable

If I open a video in the annotation tool the options to stop the video are hidden behind the list of annotations because they are hidden behind the lists of annotations. When I enlarge the tab/window "Create new annotation", the options is shown. When I enlarge it even more, the 'white box' reserved for categories gets higher. When making the tab smaller, the white box stays as big as it was.

Expected solution (see screencast: wished behavior on the right): Depending on the size of the tab/window "Create new annotation" the 'white box' should shrink/enlarge so that the options to stop the video when writing/setting annotations is always visible.

Screencast: https://tube.switch.ch/videos/eqgNdhMvJE

[jduehring]

@JulianKniephoff You can assign me here as well :D