behaviour of float windows versus visibility of the DockingManager

[trebahl]

Case 1: I create a DockingManager without adding it to a window. I define a floating window in the docking manager; the floating window appears.

Case 2: I create a DokingManager inside a Window, and show the window. I define a floating window in the docking manager; the floating window of course appears. Then I remove the DockingManager from its parent window. The floating window is hidden.

This is no bug, but I feel these behaviours are not consistent with each other. Removing the DockingManager from a visual tree should have the same effect as never having been in a visual tree at all; hiding the floating windows being my preferred choice.

A variation on case 2: instead of removing the DockingManager from its visual tree, set its Visibility to Collapsed. The floating window is not hidden. I think it should have the same effect as the original version of Case 2.

[sharpSteff]

Thanks, all three behaviours are accurate. The reason is that floating-window visibility is driven entirely by Loaded/Unloaded; there’s no Visibility handling in DockingManager at all.

So, two separate answers:

Collapsed vs. removed:
working as intended. Collapsed doesn’t fire Unloaded; the element stays in the tree and stays loaded. Tying floating-window lifetime to Visibility would mean a temporary collapse tears down the user’s tool windows, which I’d rather avoid.

Never-in-a-tree vs. removed-from-a-tree:
agreed, that’s inconsistent. It’s a follow-up to #618. That fix defers the Show() until the manager is Loaded, except when there’s no hosting Window at all, which still shows immediately so WindowsFormsHost keeps working. But Window.GetWindow returns null both for “hosted in WinForms” and “not in any tree”, and those want opposite treatment. Gating on IsLoaded instead would make it symmetric and keep WinForms hosting working.

One question: in your standalone case, are the floating windows created via Float()? A layout that merely declares them shouldn’t produce anything while the manager is unloaded, since that path is already gated on IsLoaded, so I want to be sure we’re on the same repro.

[trebahl]

@sharpSteff Thanks for your answer. Indeed the code had been written with Float(). If I create a LayoutAnchorableFloatingWindow then add it to LayoutRoot.FloatingWindows instead, it works fine.