Hi,
Im using the remote 3. Can i assign buttons when im on my page (for example living room) so that the volume buttons will always use entity x without opening the entity first? So like global assignments in the page?
No, that’s not possible. However some buttons like volume are automatically mapped to the currently active media player entitiy.
Yep. And it should be nice if user could be prompted for that auto-mapping before replacing your existing HTTP POST commands that took you hours to enter 
I’m with you on this one and we should create a feature request for this.
None of my mediaplayers are controlling volume, that’s done by my pre-amp in every activity
Just did it