Keep window in front of another window (not on top) in Windows

In Windows, is there a fairly reliable way to keep a window in front of another window?

The window in question would ideally 开发者_开发问答always have a z-order of one greater than its target.

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Owner window.

new FormToolbar().Show(this);  // shows the toolbar on top of this window.

(when this is the form that should remain 1 behind the toolbar window.