Thanks Nikolay,
Chekcing the ElementTree in the TransactionBlockEnded event handler was the missing bit. Also solved a bunch of other problems I had before when the tool window was closed or re-docked etc. Used to check for these events and call StopFlashing() in several places - the code is much cleaner now.
One has to be very careful about the order of events, your sample code for example does not work when you first autohide and then start the flashing.
This is the code that I came up with so far. It inherits from the Telerik Tool Window. You can call StartFlashing() or StopFlashing() on it, plus it stops when it becomes the active window.
using System;
using Telerik.WinControls.UI.Docking;
using Telerik.WinControls.Primitives;
namespace Octopus2.Controls
{
class FlashingToolWindow : ToolWindow
{
FlashManager flashManager = null;
FillPrimitive fill = null;
bool initialized = false;
bool windowShouldFlash = false;
public void StartFlashing()
{
windowShouldFlash = true;
if (this.DockState == DockState.Docked || this.DockState == DockState.AutoHide||this.DockState==DockState.Floating)
{
fill = null;
if (this.DockState == DockState.Docked||this.DockState == DockState.Floating)
{
if (this.TabStrip.HasChildren)
{
fill = (FillPrimitive)this.TabStripItem.Children[0];
}
}
if (this.DockState == DockState.AutoHide)
{
if (this.AutoHideTab.Children.Count > 0)
{
fill = (FillPrimitive)this.AutoHideTab.Children[0];
}
}
if (fill != null)
{
flashManager = new FlashManager(fill);
flashManager.StartFlashing();
}
if (!initialized)
{
initialized = true;
this.DockManager.ActiveWindowChanged += new DockWindowEventHandler(DockManager_ActiveWindowChanged);
this.DockManager.TransactionBlockEnded += new EventHandler(DockManager_TransactionBlockEnded);
}
}
}
void DockManager_TransactionBlockEnded(object sender, EventArgs e)
{
//
// the TabStripItem or the AutoHideTab may no longer be available when docking changes
//
if (fill != null)
{
if (fill.ElementTree == null)
{
if (flashManager != null)
{
flashManager.StopFlashing();
flashManager = null;
}
if (windowShouldFlash)
{
StartFlashing();
}
}
}
}
void DockManager_ActiveWindowChanged(object sender, DockWindowEventArgs e)
{
if (e.DockWindow.Name == this.Name)
{
StopFlashing();
}
}
public void StopFlashing()
{
windowShouldFlash = false;
if (flashManager != null)
{
flashManager.StopFlashing();
}
}
}
}