[electron-chrome-extensions] Popups using absolute positioning get incorrect dimensions

[Kilian]

The proton pass extension uses absolute positioning for much of its UI, and this means that (frequently but not always) the preferred size as reported by Electron causes clipping.

unclipped:

Size log:

{ width: 600, height: 430 }
{ width: 0, height: 430 }
{ width: 356, height: 430 }

or sometimes:

{ width: 600, height: 430 }
{ width: 0, height: 25 }
{ width: 0, height: 430 }
{ width: 356, height: 430 }

clipped:

{ width: 600, height: 430 }
{ width: 0, height: 25 }
{ width: 356, height: 56 }

or sometimes:

{ width: 600, height: 430 }
{ width: 0, height: 25 }
{ width: 0, height: 430 }
{ width: 0, height: 25 }
{ width: 356, height: 56 }

Inspecting Proton Pass it seems to do something strange by managing the popup dimensions with CSS custom properties, but then sometimes setting them to 100%. That makes me think this might be a timing issue.