Thank you so much, but it didn't fix it :(
This Telerik FilteringControl is strange, if I set a breakpoint on their Filtering event, the Filtering window seems to be on top of everything, even Windows Explorer windows! See the example below:
Maybe they are hooking into Win32 native code? Anyways, now I noticed a different problem. I attached a behavior to this filtering control so that when I click the Filter button it closes the window (it normally doesn't close it). The code is simple:
void OnFilteringControlLoaded(object sender, RoutedEventArgs e)
// When it loads and all of its children are alive find the "Filter"
// button which is the only button on the control.
// You can find out what its name is from the FilteringControl template.
this.applyFilterButton = this.customFilteringControl.ChildrenOfType<Button>().Where(b => b.Name == "PART_ApplyFilterButton").FirstOrDefault();
if (this.applyFilterButton != null)
this.applyFilterButton.Click += this.OnApplyFilter;
void OnApplyFilter(object sender, RoutedEventArgs e)
// And when clicked find the parent popup and close it.
var popup = applyFilterButton.ParentOfType<System.Windows.Controls.Primitives.Popup>();
if (popup != null)
popup.IsOpen = false;
If I call Catel.Windows.PleaseWaitHelper.Show("Please wait..."); during the filtering event the applyFilterButton.Click event is never processed! If I don't call the PleaseWaitHelper.Show it processes the click event handler just fine, do you know why??