Designer 4.7.2 or newer cannot be run under the current version of MacOS 10.15, released last week!
When starting Designer versions starting 4.7.2 under MacOS 10.15 a couple of security warnings/errors are coming up, but even by "allowing" all this exceptions Designer cannot run as expected. Even some editors (i.e. filter, data mapping, etc.) are not working and closing Designer is not possible.
According to support MacOS 10.15 is not supported and possibly will not even be supported by Designer 4.8!
Strange thing is, that Designer 4.7.1.x is working as designed - so I did some digging and found, the layout of the embedded JRE is different starting with Designer 4.7.2.x.
You can see this, if you show the contents of /Applications/Designer!
On my Mac I have two Designer instances installed, 4.7.3 and 188.8.131.52 - I changed the -vm parameter in the designer.ini of the 4.7.3 instance to the full path of the JRE shipping with Designer 184.108.40.206 and now I can start, work and close the curren version of Designer as planed!
JAVA is a strange thing!
Maybe you find this work-around useful. So far I did not run into any problems using the current Designer with the older JRE!