Why my process is jumping to the Exited event automatic ?

Question

At the top of Form1 i did:

private Process zipFileDirectoryProcess;

In the constructor i did:

zipFileDirectoryProcess = new Process();

zipFileDirectoryProcess.StartInfo.FileName = "explorer.exe";

zipFileDirectoryProcess.StartInfo.CreateNoWindow = true;

zipFileDirectoryProcess.EnableRaisingEvents = true;

zipFileDirectoryProcess.Exited += new EventHandler(zipFileDirectoryProcess_Exited);

Then i have a method that is called from a button click event:

private void Process()

{

zipFileDirectoryProcess.StartInfo.Arguments = zipFileDirectoryProcess.StartInfo.Arguments = "/select," + Path.GetFullPath(t);

zipFileDirectoryProcess.Start();

this.TopMost = true;

}

Then in the bottom i have the Exited event:

private void zipFileDirectoryProcess_Exited(object sender, EventArgs e)

        {

            this.TopMost = false;

        }

The first problem is once i click the button that call the method and start the process after few seconds automatic its jumping to the Exited event !

I want that it will go/jump to the Exited event only when i close the Process window .

The second problem once its getting to the event Exited and trying to do the line: this.TopMost = false;  im getting an exception:

Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on

System.InvalidOperationException was unhandled

  HResult=-2146233079

  Message=Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on.

  Source=System.Windows.Forms

  StackTrace:

       at System.Windows.Forms.Control.get_Handle()

       at System.Windows.Forms.Form.set_TopMost(Boolean value)

       at Diagnostic_Tool_Blue_Screen.Form1.zipFileDirectoryProcess_Exited(Object sender, EventArgs e) in d:\C-Sharp\Diagnostic Tool Blue Screen\Diagnostic Tool Blue Screen\Diagnostic Tool Blue Screen\Form1.cs:line 579

       at System.Diagnostics.Process.RaiseOnExited()

       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

       at System.Threading._ThreadPoolWaitOrTimerCallback.PerformWaitOrTimerCallback(Object state, Boolean timedOut)

  InnerException: 

How can i solve this two problems ?