When trying to update Data Modeler (22.214.171.1240) to 126.96.36.1998 in SQL Developer (3.2.20.09) using the wizard activated by Help/Chaeck for Updates ... , the wizard skips the Download step, goes to Summary and then asks to restart in order to finish the update. After restarting SQL Developer the Data Modeler is still the old one.
I've defined the browser and web proxy in Preferences. The proxy test is successful.
This is a recurring problem which I have also encountered with other extensions. The download step isn't actually skipped, it just downloads a zero-length file. The file exists so SQL Developer tries to load it on restart but fails. Repeating the exercise just downloads a new version of the empty file.
It is another symptom of Oracle's generally flaky download servers, and I have never solved it satisfactorily.
There is workaround which involves obtaining the file by other means and then selecting the 'Install from local file' on the update dialog box.
Getting hold of the file by other means is a whole other problem...