Malformed trade chat & dispute speech bubbles

[stejbac]

Description

In the trade chat window and mediation chat pane, sometimes the "arrow" of a speech bubble is rendered on the wrong side (observed: left hand side instead of right), pointing into the bubble as seen in the screenshots below.

Version

1.2.3 and latest snapshot of master (2019/11/21).

Steps to reproduce

(I haven't attempted to reproduce it yet - observed on one actual mediated trade.)

Expected behaviour

Each speech arrow is placed correctly, such that it always points outwards.

Actual behaviour

Arrows are intermittently placed on the wrong side of the bubble (although apparently always in the right orientation), so that they point into it. The rendering error is not consistent and sometimes a given individual speech bubble is rendered correctly when viewed later, e.g. after restarting the application. Also, I've observed consecutive speech bubbles from the same sender render correctly then incorrectly (or maybe it was the other way round?).

Screenshots

Device or machine

AMD64 Debian Linux (HP laptop)

Additional info