Oh wow, thanks for the 'investigations' about that bug. I think I understand the problem here although I only do a bit programming in C/gcbasic for 8051/arduino microcontrollers and TCL/TK by myself **;-)**
I can imagine that if it's possible to run JS in the webview, this would be a workaround. But hey, if it's too time consuming for you, I fully understand. Geany is already a cool tool for coding a bit and write some markdown-text.