Basic inheritance question (inherit from DataGridView)

[Michael Howes]

I added a new user control
I went in and changed the control to inherit from DataGridView
I want my new DataGridView to have a fixed number of Rows and Columns
so I have a method I call in my inherited classes constructor with two
loops adding the rows and column along with setting the width of the
columns and height of the rows.

Everything is going good so far.

Now I drop my new control on a form and my first surprise I see my
columns in design mode. The constructor was called? What's going on here?

At the beginning of my method that adds the rows/columns I call
..Clear() to remove any existing rows/columns.
I run the application, and surprise #2 shows up, which is I have
double the number of columns. I had a breakpoint and the method that
adds rows/columns was only called once.

What's going on here? Where are these extra columns coming from?

And maybe a better question. When inheriting from a control in this
way where/how is the best way to have a fixed set of settings?

thanks
mike