Hello sql developer team!
Firstly I want to say - I like SQL Developer a lot and use it every day, but...
Here is the screenshot of the SQL Developer 18.1 and Windows Explorer (for comparison) on my notebook. I hope, you can see the display differences.
I need a screen magnifier to work with this version of sql developer.

Here is the next screenshot with look and feel set to "Windows":

On the second monitor with screen resolution 1920 x 1080 has the sql developer no problems.
I had the same behavior with sql developer 17.4 too. But there was it only when I turned on the instance viewer! Is this a java problem?
I use the "Windows 64-bit with JDK 8 included" version of sql developer 18.1.
Operating System: Windows 10 Professional
Notebook screen resolution: 3840 x 2160
Thanks