OpenGL: Drawing very thin triangles with TriangleList turn into points

I'm using TriangleList to output my primitives. Most all of the time I need to draw rectangles, triangles, circles. From time to time I need to draw very thin triangles (width=2px for example). I thought it should look like a line (almost a line) but it looks like separate points :)

Following picture shows what I'm talking about:

First picture at the left side shows how do I draw a rectangle (counter clockwise, from top right corner). And then you can see the "width" of the rectangle which I call "dx".

How to avoid this behavior? I would it looks like a straight (almost straight) line, not as points :)

This is the problem of skinny triangles in general. For example, in adaptive subdivision when you have skinny T-junctions, it happens all the time. One solution is to draw the edges (you can use GL_LINE_STRIP) with having antialiasing effect on You can have:

Gl.glShadeModel(Gl.GL_SMOOTH);
Gl.glEnable(Gl.GL_LINE_SMOOTH);
Gl.glEnable(Gl.GL_BLEND);
Gl.glBlendFunc(Gl.GL_SRC_ALPHA, Gl.GL_ONE_MINUS_SRC_ALPHA);
Gl.glHint(Gl.GL_LINE_SMOOTH_HINT, Gl.GL_DONT_CARE);

before drawing the lines so you get lines when your triangle is very small...