Category Archives: UX

WPF Popup focus nightmares

We have a fairly advanced windowing system for the app I’m developing, and one of the side effects is that when using controls inside a Popup control, the keyboard focus does not always behave correctly for the controls inside the popup.

I found this great article which immediately solved my problem :

The root cause of my issue is that a Popup’s HWND has the WS_EX_NOACTIVATE flag set, meaning that the focus is not set properly.

Credit to Philipp Sumi and Andrew Smith.



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Filed under UI Hints, Useful, UX, WPF

The great WPF ToggleButton and Popup Conundrum

For a while now we’ve been using a very simple pattern for opening custom popups by binding to the IsChecked property of a ToggleButton. It’s simple, needs no code-behind, and works 99% of the time.

However, it has a very annoying 1% which is the following:

  • You want your popup to open when the toggle button is clicked – OK
  • You want your popup to close when the user clicks elsewhere – off the window, etc – OK
  • You want your popup to close when you click the toggle button again- BUT THIS DOESN’T WORK

The reason is because the events happen as follows:

  • Open the Popup by clicking on the Toggle Button
  • Click on the Toggle button again
  • Before the “Click” is processed by the toggle button, the Popup handles the fact that the user has clicked elsewhere and so closes
  • By closing, the popup sets the IsChecked state of the toggle button back to unchecked via the 2-way binding
  • Now the “Click” is handled by the toggle button, but at this point the popup is closed, and the toggle button is not checked, so it re-checks itself, and re-opens the Popup !

The Solution

Many people have tried to solve this by using Timers, behaviours, fiddling with the Binding, but there is an annoyingly simple solution:

On the ToggleButton set the Property ClickMode=”Press”

…and you’re done…


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Filed under UI Hints, UX, WPF

An “excellent UX design”

This UI is described as “excellent” , “elegant”, and “clear and compact” :


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Filed under UX, WPF