The Geometry Viewer in pgAdmin persistently captures the keys 6, - and _ after switching to another tab without first removing focus from the map. This can be recreated by performing the following steps in either Firefox, Edge or Internet Explorer (but not Chrome) in pgAdmin 4.3 on Windows 10:
Opening a Query Tool... for a database with PostGIS installed.
Running a query that returns a geometry, for example SELECT ST_SetSRID(ST_MakePoint(0, 0), 4326);
Clicking the View all geometries in this column button.