I have issue with UltraDesktopAlert, First i am showing desktop alert, then i calling 3rd party library's Show Form Dialog method from Reflection.
so when desktop alert is disappear that time, its close my 3rd party's open dialog.
My guess its internally desktop alert become parent form of my 3rd party's dialog, so parent form close so does child form.
so I just want to open UltraDesktopAlert in New Separate Thread.
Attempting to open the UltraDesktopAlert in a separate thread is actually a bad idea as all UI interaction should occur on the UI thread. It may work to display the UltraDesktopAlert in a new AppDomain. However, doign so would really just masking the underlying issue.
Based on your description, it sounds like the Form used to display the UltraDesktopAlert is becoming the parent of this third-party dialog. The UltraDesktopAlert does not manipulate the parent of other forms. My theory regard this issue is that the when the UltraDesktopAlert is being shown, it becomes the ActiveForm within the AppDomain. When this other dialog is being shown, it finds (or your reflection code) is finding the ActiveForm and using it as the parent.
Try calling Activate() on the main form of your application prior to the call do display the third-party dialog. Please let me know if this works.