How to continue drawing an interrupted Mask in After Effect

It's frustrating in AE  that if you interrupt the drawing of a Mask, the app makes a new Mask instead of continuing the first one.

First be aware of the interruption, then go back to the Pen Tool, select the Convert to Vertex Tool, and then click on the last point of your interrupted Mask.

Then go to and select Pen Tool again, and continue to draw the same Mask. Aaaah!