I uploaded a new test version to the
second post, it fixes a problem reported
here. I was not really able to solve the reported problem, so I had to work around it by replacing it with a button and a dialog combo. This problem was introduced by
changes in calibre version 5.33.2. Given that no one reported it till now, it seems that this particular widget is rarely used, so the workaround is not going to be a big problem.
The new version also changes the way the predefined single field edit widgets are implemented for all fields. The change is done improve the readability and maintenance of code.
So I like to get confirmation that all is working well before releasing it. Since it now stacks all the predefined widgets instead of loading it at demand, it might lead to a slight lag.