Created attachment 180010 [details]
A document with the bug manifesting
Consider the attached document. It's originally imported from MS-Word, and contains different sections, as well as a section with two columns - but I've removed almost all of the content, so it's basically mostly Heading 1's and Question paragraph style (where the outline level of Question is 2).
Now, in the ToC of this file, there's a page (or column) break before the entry for the 7th section. I'm not sure why that is. It is also a rather brittle phenomenon, i.e. all sorts of changes make it go away, and I can't quite characterize exactly when it manifests. I can say that if I remove enough ToC-represented items so that everything fits in a single column, then the page break disappears, but there are other ways to make it disappear too.
The document is RTL, but I don't know that this matters.
Created attachment 180026 [details]
Screenshots before and after Ctrl+Enter
Two columns of same lenght when just opened the document.
Version: 188.8.131.52 (x86) / LibreOffice Community
Build ID: e1f30c802c3269a1d052614453f260e49458c82c
CPU threads: 4; OS: Windows 6.1 Service Pack 1 Build 7601; UI render: Skia/Raster; VCL: win
Locale: es-MX (es_MX); UI: en-US
May be a screenshot of the original poster could add to explain the issue.
Created attachment 180028 [details]
Screenshot of bug manifesting
(In reply to LeroyG from comment #1)
> Two columns of same lenght when just opened the document.
So, that's not what I'm getting. But - please check with a recent nightly.
> May be a screenshot of the original poster could add to explain the issue.
This should be fileopen bug, just see ToC.
No repro in Win, like LeroyG, repro in Linux with 4.1 and 7.4+, regression.
Regression around 3.6. In 43all it's a rather large range: