Active all window on the main form

[Wizard001]

How to do in Visual C# that few windows (for example tools window, drawing window and etc.) will be active at same time.

[Machaira]

Only one window can have focus at a time.

[jmcilhinney]

As Machaira says, you can only have one active window. If you mean how can you stop those windows disappearing behind the main window, like the Visual Studio Find and Replace dialogue, you need to make them modeless dialogues by using code like this:

Dim myDialogue As New Form

Me.AddOwnedForm(myDialogue) 'or myDialogue.Owner = Me
myDialogue.Show()

If you do this, whenever the main window is active the dialogue will still be in front of it, even if it's not active itself.