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FContinueMessageLoop marks hidden modal dialog forms for closing

I am opening multiple modal dialog forms (2) one on top of the other. I hide the modal dialog forms along with their parent and open the Microsoft Word application. A short while after calling the Hide method for each form I noticed that the system calls the Close method automatically for each of the forms as a result of running FContinueMessageLoop (I noticed this in the StackTrace).
After reading this forum entry, I found out that this might be caused by cross-threading issues but the author is not very specific.
Does anyone know which are the situations in which FContinueMessageLoop decides that a message loop should be terminated?

How to show a Wait cursor using C# without having an active (or any) Windows Form?

I have tried using this code sample:
private void DoShortRunningTask()
{
using (new StWaitCursor())
{
Thread.Sleep(5000); // 5 sec delay.
.. do some work ..
}
}
From: http://www.codeproject.com/KB/cpp/WaitCursor.aspx
But it did not do anything for me, since I did not have a main form. I do not need a main form. My C# project type is Windows Application, but the only GUI it shows if any is error or success messages dialogs. Is there a way for me to fake the existence of a WinForm (so that it exists but is not visible)? Would the mouse cursor have to be over it in order to show up?

I don't think it would be good practice just to change the cursor when it's not in your UI. You wouldn't want another program messing with the cursor in your UI. If you just want to show that your application is running, have you thought of using a tray app. These are relatively simple to create.
Here's an example I just googled:
http://alanbondo.wordpress.com/2008/06/22/creating-a-system-tray-app-with-c/
You can also show speech bubble messages as your run progresses etc, if you want to let the user know things are happening.

I do not need a main form
Yes, you do. Any UI interaction needs a form, sorry.
way for me to fake the existence of a WinForm (so that it exists but is not visible)?
How is that faking?
Make a form, make it invisible (transaprent - check all the properties on the form class and you will find it) and finished ;) Standard approach. Also tell it not to show up in the forms collection in the bottom of the screen and minimize it and you are finished. nothing fake here.

TomTom++
Are you just wanting to change the current cursor?
Try this
http://www.csharp-examples.net/hourglass-wait-cursor/

Need Suggestion for my app

I want to show an loading image when i launch my desktop application. can anybody tell me how to show this in C#? Results required as happens in visual studio 2005/2008 when we launch this application.

What you are looking for is actually a splash screen. Look at this codeproject article. It explains really well how you should do this.
http://www.codeproject.com/KB/cs/prettygoodsplashscreen.aspx

What i did in my previous project was, that make the Form1 (display form) and make it wait for a while, then close it after that launch the Form2 which is the actual application.
But that was way back when i was a fresher. Now what i might do is, have a Form1 which ill launch and in the backgroundworker do all major UI processing work such as if any loading of data needs to be done, etc stuffs and keep every thing ready in memory. Then ill close the Form1 or make it hide or invisible and launch the Form2 which is the main app form and pass all the information required to it.

C# - Possible to safely have an owned form in a separate thread?

I am attempting to write a specialized onscreen keyboard (OSK) for an application I'm writing in C#. To facilitate this, I've created a form which has several buttons on it representing keys, and clicking them calls SendKeys and sends out the appropriate keys.
This form is owned by the main window that is shown when the application first starts, using the Owner property. This way, the OSK pops up whenever the user focuses the application, and it stays on top of the main window if it said main window is dragged over it.
This all works great, but because I have modal dialogs that I also want to use with the OSK, I attempted to create it in a separate thread, complete with its own message loop (via Application.Run) so it could still be usable with any modal dialogs in the main thread.
The problem with this is that, obviously, being in a separate thread can cause InvalidOperationExceptions because of cross-threaded calls. One specific example of this is when calling Application.Run(osk) from the new thread, a cross thread error occurs because it is attempting to update the window's handle with the owner (the main window).
My question is, is it possible to have an owned form on a thread that is separate from the owner in a safe manner? And, if failing that, is it possible to emulate an owned form's characteristics (namely being Always On Top for only the main window, and popping up when the main window is focused)?
Thanks, and sorry if this is confusing.

I think this is actually a bug in Windows Forms. Somewhat inevitable due to the way it checks for access to the Handle property by the wrong thread. The SDK docs for SetParent are not explicit about it, it states the requirement is that both windows belong to the same application. No mention of having to belong to the same thread. I know for a fact that the 'same application' requirement is not hard, there's appcompat code in Windows that makes this work for windows from different processes. Adobe Acrobat ab/used this for a long time. Which definitely absolves the 'same thread' requirement.
Well, punt the problem and try it out. Set Control.CheckForIllegalCrossThreadCalls to false before you set the owner, back to true afterward. And test the heck out of it. If you have trouble then try pinvoking SetParent() directly instead of setting the Owner. Windows Forms actually uses SetWindowLongPtr which is not recommended by the SDK.

I'll take a stab at this. Try running the OSK as a separate process.

Try using ShowDialog for the OSK as well instead of Application.Run - ShowDialog creates a message loop and ends it when the window is closed, and perhaps will solve your problems.
new Thread(() => new OSK().ShowDialog());

Why not use Control.Invoke to make cross-threaded calls to avoid InvalidOperationException?

Opening a file in C# using a modeless openfilediaglog box

I'm trying to make a video recording application for a project and was wondering if there was anyway to make the OpenFileDialog open up in a modeless diaglog box or would I have to make my own custom version? The reason I ask is the ShowDialog() function freezes my video. Thanks in advance for the help.

Yes, you can prevent a file dialog from blocking the UI thread, but it can be rather non-trivial depending on the details of how you want it to behave. If you're open to buying a component that does this automatically, ComponentAge offers one. Otherwise, you can roll your own by opening the dialog on a spawned thread. If you want the dialog to appear modal to the form that opened it, you'll need to do some extra work to trap the handle of the opened dialog so that you can set focus to it when the parent form is activated. An example is available at http://www.codeproject.com/KB/dialog/CustomizeFileDialog.aspx.