Pixel Hunt Required to Resize Console Pane

**IDE version:** 1.8.12
**OS:** Ubuntu Studio 18.04 LTS
**JRE:** OpenJDK Runtime Environment 11.0.6+10-post-Ubuntu-1ubuntu118.04.1
**DE:** XFCE 4.12 (GNOME and QT/KDE libs installed)

As the title mentions, resizing the IDE console window requires a pixel hunt. It would appear that the resize area is a single pixel in height.

Here's a [Google Drive link](https://drive.google.com/open?id=19xl0Ew-pXI4QNi_4-aiIt-QE_dPn_W4M) to a quick video screenshot of the issue.

As can be seen from the video, there's no real visible resize handle, and what intuitively should be the resize handle is ridiculously small.

Can this be readily fixed? I'm not a fan of Java, but if the code for this isn't buried to deep and I can get a direction on where to look for this in the source, I can give a shot at finding the issue.

No source file or test is named. Start by locating the Arduino IDE 1.x console pane and its resize handle, then reproduce the one-pixel resize target on the reported Ubuntu/XFCE setup; done means the console can be resized through a clearly usable handle.

Written by the indexing model from the issue text.