Comment # 19 on bug 749440 from Frank Kruger

(In reply to Peter Gumbrell from comment #18)
> Reopening. Bug still present on Leap 42.3 with default Thunderbird 52.x. Not
> sure about Leap 15 but I won't hold my breath. See comments 14 or 16 above
> for summary.

The bug also shows up in Leap 15.0 Build 206.1 with Thunderbird 52.7.