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How to handle mouse events from user control while ignoring those of its controls

Screen of my user control
I have an user control (black rectangle) that contains some controls.
When the mouse is hover the user control, I want to show the two images in the red rectangle.
At the moment I have implemented the mouseEnter (show the images) and mouseLeave (hide the images) events from the user control.
The problem is that when the mouse is hover another control (a label for instance), the mouseLeave event from the user control is fired and the images disappear.
I could implement the mouse enter / mouse leave events for all the controls but it seems a waste of time, lots of code deduplication and a poor usage of memory.
I also thought about disable events for the other controls, but not sure how to do it and it seems to be more of a hack than anything. Il tried to disable the controls but the color changes and again, a dirty hack.
Maybe I can prevent the user control mouseLeave event to be fired if the mouse is hover one of its control ?
I'm sure there is a proper way to do it, but cannot figure it out.
If anyone thinks about a better title, I will change it.
Thank you for your help,
Regards

Thank you very much both of you.
You pointed me to the right direction.
I ended up to simply register the ControlUser.MouseEnter event to all controls by doing :
foreach (Control control in Controls)
{
control.MouseEnter += new EventHandler(this.MyUserControl_MouseEnter);
}
Simple and efficient, this is perfect.

WinForms ScrollableControl's scrollbars capture mouse wheel?

I have a custom ZoomBox control based on ScrollableControl which controls its scrollbars through AutoscrollMinSize property.
I would like to be able to handle WM_MOUSEWHEEL events to adjust control's Zoom.
I made necessary steps to make sure that the control receives the mouse events even when it is not in focus, by filtering them on the parent form.
It seems though that the events only reach the OnMouseWheel method if the control does not have its scrollbars active. If it does, it appears that the mousewheel events are being redirected to the scrollbars which handle them (by scrolling).
I would like the scrollbars to be there but only be controlled in a "traditional way", i.e. by dragging the slider or clicking on arrows etc. and handle the wheel myself. Is it possible to achieve that?

Inherit from the ScrollableControl in question and override OnMouseWheel(). In that method don't call base.OnMouseWheel().
As far as I can tell there's no other way to stop ScrollableControl from scrolling if the scroll bars are present.
A side effect is that you will no longer get MouseWheel events. Fixing that is another question. Conceptually you want to call base.base.OnMouseWheel().

C# Winforms How to draw a rectangle on a button on a mouse over?

In our application we have white buttons on a white form. When the mouse hovers the button we want to show a light-blue transparant rectangle over the button.
I want to create this user control, but I don't know how to do this. I've tried google, but I didn;t found anything that could help me, so I hope you guys can point me at the right direction.

You can just derive your own WinForms control from a Button and override the OnPaint event. In the event handler you'll have an PaintEventArg parameter that contains the property called Graphics. You can use this property to draw anything you want directly where you control is located.
Here is an example directly from MSDN: http://msdn.microsoft.com/en-us/library/system.windows.forms.control.onpaint.aspx
Added: just re-read your question and found that I didn't not reply it correctly.
Basically, you have to override two events and add one property showing whether your control should be painted with an overlayed rectangle or not, let's say IsDrawRectangle. As soon as the OnMouseEnter event is triggered you check if IsDrawRectangle is set and if not you set it to true and invoke this.Invalidate(). The Invalidate() method will force the control to be re-drawn and then in your OnPaint event you just again check the value of your IsDrawRectangle property and draw the rectangle if needed.
You also have to override OnMouseLeave to set the property back to false and force the repaint to remove the rectangle.
Added: if you need to re-draw more than just a single control (in case if your rectangle covers some other controls that need to be re-drawn) then put everything you want to be re-drawn in one container and call the Parent.Invalidate() method in your event handlers.

How to fix scrollbars when the window or container is resized?

Currently in my application I am using the HScrollBar and VScrollBar for panning around in a large image. The part of the image that is shown is based on the scrollbar's Value property. However, when resizing the SplitContainer or resizing the form window the scrollbar's Value does not automatically update and it may render something off-screen.
At this point I noticed that if you clicked the scrollbar's arrow it magically fixes the scrollbar. I was wondering if there was any way to simulate clicking the scrollbar to do this in the Form_Resize and SplitContainer_Resize event handlers but I couldn't find anything.
Having to manually adjust the scrollbar's value in all resizing events is slow, ugly, and doesn't work well. I'd really like for the scrollbar to just automatically fix itself when the window resizes like it does when you click its arrow but I'm not sure how.

Try calling the scrollbar's Invalidate() method in the form's resize event handler:
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.invalidate.aspx
That should cause it to redraw correctly after the form is resized.

Use something like this:
HScrollBarObject.SetStyle(ControlStyles.ResizeRedraw, true);

Container Control is losing focus

I'm trying to create User Control which will work like a rich button.
It's supposed to have an effect on hover - I turn border on on MouseEnter and off again at MouseLeave.
BUT, when I hover over label in my control, it fires Control.MouseLeave.
Is there any way to prevent this?

First, focus Enter and Leave are different events than MouseEnter and MouseLeave. Focus deals with keyboard input. MouseEnter and MouseLeave deals with where the mouse is right now.
Entering a nested control fires MouseLeave on the parent control. You can capture the mouse by setting the control's Capture property to true, but you may find that doesn't behave like you'd expect.
You might look at my post here. I had the same issue with nested controls. I opted to create a .NET equivalent of a mouse hook by calling Application.AddMessageFilter.
Another option would be to remove the inner label control and draw the text manually it in the button's OnPaint.