Support `iframe` based editors to reparent into floating windows

[bpasero]

With floating windows, users have the desire to move editors out of the main window into the child window. Some of our editors use an absolute positioned iframe element that is resized and moved to fit into the editor area it belongs to. This will not work anymore as soon as the editor moves out of the window.

I already made a pass and configured currently unsupported editors with the new AuxWindowUnsupported capability.

This impacts custom editors as well as notebooks.

Steps to move an editor out to a floating window:

• remove the AuxWindowUnsupported capability for the editor of choice
• open such an editor
• trigger the "Move active editor into a new window" action from the command palette

//cc @Tyriar

[r3m0t]

Can I work on this one? My interest is in the notebook editor.

Is it possible to use DOM appendChild to move the iframe from one window to another?

Maybe retainContextWhenHidden: false is an easy case that can be done first? In this case the editor iframe can be safely destroyed and a new one created.

[bpasero]

@r3m0t thanks for willing to chime in, I think @rebornix has already started on this so maybe he could comment

[r3m0t]

@bpasero any of these 'help wanted' or no? https://github.com/microsoft/vscode/issues?q=is%3Aopen+label%3Aworkbench-auxwindow

[bpasero]

Thanks for asking, maybe #196148 or #196579. The others seem rather complex to me.

[abrahan-munro]

This issue is hard to find as it doesn't contain the text of the error message, so I'm adding that now:

This type of editor cannot be opened in other windows yet.

Also, an explicit list of windows that are affected would help with searching, e.g.

• markdown preview
• extensions