Video freezing, seems related to Remote Host pane

I'm encountering some freezing issues with PhpStorm on Ubuntu, with both the previous release and the current (2017.3). I run my Remote Host and Project Files panes in Windowed Mode, and I have noticed that sometimes either of them will act as if they're "Always on Top", most frequently the Remote Host window. The Remote Host and Project windows are generally on my main display, whereas the IDE itself is on a secondary portrait-orientation display to the right of the main one. 

I also find that the whole OS predictably/replicatably freezes and requires a hard shutdown (hold power button) when I do the following:

1. Open PhpStorm with Project Files and Remote Host windows on main display while IDE/code editor is on secondary display
2. Open full-screen Chrome browser on main display
3. Switch back to PhpStorm and use hotkeys to display Remote Host or Project Files windows

System specs:

Dell XPS15 (9650) with Ubuntu 17.10 + Gnome 3.26.2

This laptop has both INtel and Nvidia video hardware, but I'm able to replicate the issue while using either chipset. Any suggestions? Different JDK/JRE maybe?