How to implement the effect when draw the geometry

I developed a program based MapwinGIS, but when I draw a polyline or polygon (Based on function shp.InsertPoint and shpfile.EditInsertShape(shp, ref index)), the cursor did not have the effect like the below picture

but the effect like the below picture. There is no line between the third point and the second point. But I can finally finish the line drawing

and if I use the tkCursorMode.cmMeasure, when I change the mode to tkCursorMode.cmPan, how to continue to use the tkCursorMode.cmMeasure on the last point of just edited line or polygon ??
Can someone point out my problem?

Are you using the ShapeEditor Class?

Showing some relevant parts of your code will also help.

Thank you ! I tried the simplest code, my question is when I change the cursor mode from cmMeasure to pan, the line is disappear, I want to implement from cmMeasure to pan, and move the map, and then from pan to cmMeasure, and continue to draw the line

  private void btn_Measure_Click(object sender, EventArgs e)
        axMap1.CursorMode = tkCursorMode.cmMeasure;

    private void btn_Pan_Click(object sender, EventArgs e)
        axMap1.CursorMode = tkCursorMode.cmPan;

or can you show me the source code of tkCursorMode.cmMeasure, I did not find it in the MapWindow5-5.6.3_Code. In addition , I found the solution from your answer “At this moment holding the ‘spacebar’ is used to pan.” . So I want to know why I change the mode by tkCursorMode.cmPan, is different from the spacebar when I draw the line.