See https://mahara.org/interaction/forum/topic.php?id=7664
If a block has no title, it can't be collapsed. That is, if you set the "Collapsible" setting to "Yes", the block can't be toggled because there's no title bar to click on. Moreover, if you set the block to "Already collapsed", it won't be displayed as collapsed, or collapsible.
This behavior is present at least as far back as Mahara 1.7. I've found this behavior in the Text and Image blocks, but I haven't tested it across all of them so I don't know whether it's part of the implementation of particular blocks, or if it's in the block library code.
To replicate:
1. Put a text block on a page.
2. Delete the block's title.
3. Give the block some text.
4. Set the block's "Collapsible" setting to "Already collapsed"
5. View the page in display mode.
Expected result: The block is collapsed, and can be toggled between expanded/collapsed.
Actual result: The block is expanded, and there is no collapse/expand toggle to click on.
Ah, this was actually part of the initial implementation of collapsible blocks: https:/ /reviews. mahara. org/#/c/ 1678/
There's even a comment from Hugh about the "collapsible" setting on the config screen: "Perhaps add a rule so that a warning is shown when this is set with an empty title?" But it looks like we never followed up on that.
I'm not sure what the best solution is here. Display an empty title bar, with just the toggle control? Or disable the "collapsible" options when the block has no title?