google maps - How to create a custom GControl -

I'm trying to create a gray "frame" (see picture below) around a Google Map, focus The concept of a field, opposed to a point (which is usually depicted with a marker) Note that this is not an overlay, that is, the gray "frame" should not be moved when you drag the map.

Edit: Image Link Added

It seems that I have the option of "subclass" GControl to create a custom control. There are 3 questions

1) First of all, is giccontrol a subclass of best action?

2) In my example, the canvas (div) where the map changes, it can change the size (i.e., not the fixed width), on the canvas size change, do I have to delete and add custom controls? See the documentation for creating custom map controls.

3) Now, how to do it. Naively, I thought I could create a table with 3 columns and 3 rows, and set the display: None in the middle for the cell but it does not work I have also experimented with clipping, which That does not work either. The lack of my CSS skills is considerable, so it should be a way of doing it more beautifully than adding four rectangular gray ones. If I wanted to add an internal border, with divs, I would need to paint 8. In short, what is the best way to create a "hollow" rectangle?

Thanks PS This is my first entry in stack overflow just to find it. It's impressive how well it is put together.