GTK crash when downloading multiple files

[tril0byte]

Description

Crashes when downloading multiple files at once.

Steps to Reproduce

1. Go to https://cdn.openbsd.org/pub/OpenBSD/6.6/arm64/
2. For each .tgz file in the list, left-click it and choose to save it to disk. Click on them rapidly in succession to get multiple files to be downloading at the same time so at least sometimes one is downloading before the previous completes. If you download one at a time it seems stable.
3. Dissenter crashes.

Actual result:

**
Gtk:ERROR:/tmp/buildd/gtk+3.0-3.14.5/./gtk/gtkrbtree.c:465:_gtk_rbtree_insert_after: assertion failed:
(_gtk_rbtree_is_nil (tree->root))
/usr/bin/dissenter-browser: line 48: 1617 Aborted "$HERE/dissenter" "$@"

-OR-

/usr/bin/dissenter-browser: line 48: 15298 Segmentation fault "$HERE/dissenter" "$@"

I have seen both errors but Aborted is more common.

Expected result:

Reproduces how often:

I have experienced 3 crashes of dissenter when repeating these steps, seems reliable.

Brave version (brave://version info)

Version 0.70.122 Chromium: 78.0.3904.87 (Official Build) (64-bit)

Version/Channel Information:

• Can you reproduce this issue with the current release? Unsure...I keep getting pop-ups for updating Dissenter but the version I'm running is the same as the one on the website.

• Can you reproduce this issue with the beta channel? didn't try

• Can you reproduce this issue with the dev channel? didn't try

• Can you reproduce this issue with the nightly channel? didn't try

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? didn't try
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? didn't try

Miscellaneous Information:

Using tiling window manager xmonad