request: improve Separated Mode & two monitor support

[thomaso]

This feature improvement request is currently relevant in Separated Mode and when using two monitors.

Some users of a laptop have a 2nd monitor connected which allows to place document windows on the larger screen and panels on the smaller. Unfortunately for a custom panel arrangement Affinity currently demands to switch to Separated Mode.

Separated Mode also separates document windows by default. Also new windows get opened on the 'main screen' (e.g. the laptop's internal), regardless of its size (resolution) and of already existing document windows on the other screen. That way any new document window appears covered behind panels and is therefore 'invisible'.

To combine these document windows as tabs in 1 window the user needs to select "View" > "Merge All Windows" – every time a document gets opened.
Unfortunately to do so it also is necessary to first select (activate) the already existing window, otherwise this command moves all documents to the newly opened document on the unwanted screen and behind the panels.

Requests:
a.)  enable a Separated Mode which does not affect document windows but panels and toolbar only.
b.)  make new document windows open on the screen which already shows a document window.
c.)  remind in Separated Mode the document window size and position.
d.)  allow to auto-fit document windows between panels instead of behind them in full screen size.

Or:
e.) improve the Not-Separated Mode by enabling custom panel + toolbar arrangement on 2 monitors.
This would have the same result as a) + b) + c) + d).
Since in not-separated mode the panel docking and sticking works better than in separated mode this option e.) is the preferred towards a.) – d.) for users who still want to arrange panels as groups around the document window and currently use separated mode just to make use of 2 monitors.

Example setup of two monitors (macbook internal + larger external):

Same example with menubar, Affinity panels, toolbar and document window:

New documents open on smaller screen, covered behind panels: