On 10-02-18 17:47, Luís Marques wrote:

On Fri, 09 Feb 2018 22:30:24 GMT, Luís Marques wrote:

On Fri, 9 Feb 2018 23:11:13 +0100, Mike Wey wrote:

Is the drawing handler actually called? you may need to invalidate the
DrawingArea by calling queueDraw in the OnFocusIn handler.

Yes. I'm sure about that.

Any more ideas?

Unfortunately no not currently.