GIMP 2.99/ Python 3 trouble with dropdown widget

I wonder why in this trial script

the dropdown widget does not show properly. It looks like this:

Yes I have been trying to get this to work too but with no success. I have given up temporarily because there seem to be a lot of changes happening as Gimp 3.0 approaches. Hopefully there will be some documentation when the Release Candidates appear.

Looks like I have finally found a solution. But it looks ugly. Some elements are aligned to the left, others seem to be centred. But at least they all show properly.

For those interested, the code is here:

Thank you for the update. I have just tried the syntax you have used and at last have a proper combo box for making choices. Now I can progress some of the plugins that I regularly use and which require conversion to run in Gimp 3.0 (I hope!)

About the alignment, this is being tracked at: [2.99.19] The Dialog Nick Text on Python Not unified Alignments (#11261) · Issues · GNOME / GIMP · GitLab