So I decided to use rich text formatting in one of my posts the default forum editor doesn't support (strike-through). Copied stuff to Word, formatted it, then copied back and submitted the post.
The thread broke with the bottom part missing and reply/edit/delete/report etc. buttons also missing. I managed to fix this by using a browser plugin to locally edit the page source, so I could do some magic and force those buttons to appear, then I could delete the post that broke the thread. Everything want back to normal.
My suggestion: The box we type into when posting stuff here shouldn't accept just any pasted rich text, especially not from MS Word. The forum software just inserts this rich text into the HTML code and sends it straight to our browsers. The thread breaks because of the invalid HTML code.
CPU: AMD Phenom II X4 810 @ 3120MHz | RAM: Kingmax 2x2GB DDR2 800 @ 833MHz| MoBo: MSI K9A2 CF v1.0 (BIOS: 1.D)| GPU: Asus HD 6850 1024MB (DirectCu) @ 835/1135MHz | Display: L24FHD | PSU: PC Power & Cooling Silencer 750 Quad | OS: MS Windows 3.11 Pro x64