Problems with Refresh in Visual C# 2005

Hi everybody!!!
First of all, sorry for my bad english.
I´m begginer in OpenGl. I use Tao Framework to have a control where draw.
In my application i draw signal_1, clear control with Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT), and the paint signal_2.
But when i move over the form of the control another window, signal_2 disappear and signal_1 appear.if i move the window over the opengl control slowly signal_2 and signal_1 alternate.

i forget clear other buffer?

My opengl initialization:
Gl.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
Gl.glShadeModel(Gl.GL_FLAT);
Gl.glEnable(Gl.GL_DEPTH_TEST);
Gl.glEnable(Gl.GL_CULL_FACE);

Thanks in advance.

Please clarify with more detail.

You need to draw it to the same context etc to have them in the same window. Make sure that MakeCurrent is called for the appropriate context at the appropriate time especially if you’re single threaded with multiple windows.