Experiencing GUI delays in Oracle SQL Developer

I use the Data Import Wizard (DIW) for file loading. And lately, simply right clicking on a table and then selecting the DIW option to bring up the wizard, I experience a 1-2 minute lag before the GUI dialog box even comes up. Furthermore, as I progress thru the steps of the DIW GUI, each step will delay 1-2 minutes before moving on to the next. So all together, using the DIW can typically take me > 10 min.

What could be causing this and how might I remedy the issue?

I'm using Oracle SQL Dev version: 18.4.0.376

Regards, rhelm