The problem is this – I have a main form (parent) with a menu and several other forms which are children I want them to load in the main form. The problem that I met is – the child form is loaded within the main form(parent) but it looks like a separate window. This:

And it not only stays like window within a window but also don’t get resized when the parent is which seems logical but is not what I want.
What I want is something like this :

I want the child forms to be loaded without the window controllers for minimize, maximize, close, the blue line and all that stuff but instead to look like a part of the parent window and respond to some parent events like resize.
Try adding the following code into your children windows (and subscribe on FormLoaded event)