This mod adds a new bbcode tag that will hide what you wrap with it.
Use the new H button or use [hide]Your hidden text[/hide]

It works with text and images. Clicking on the spoiler show button, reveals the block but you need to have participated in the thread. Guests can not view the hidden text.

This is a new version, rewritten for 10.3.6 and I've added it to the Quick Reply box also.

NB: ALWAYS BACKUP YOUR FORUM BEFORE INSTALLING A MOD