How to get spaces in TOC

I create paragraphs labelled ‘Section A’ and ‘Section B’, and give them style ‘Header 1’, and have automatic
numbering enabled.
I then insert a TOC, and it looks like this:
1SectionA 1
2Section B 1

How can I most easily get one or more spaces inserted between the number and the name ?
e.g.:
1 Section A
2 Section B

That is done in the TOC dialog. Click on the tab “Entries”. There you can determine, how the lines of the TOC look like. Click after button E# and then you can enter a tab stop or press the space bar. That can be done for each level separate. Or you copy the structure of the first level to all levels by clicking on the All button. Find a short explanation of the parts in the help.

Old problem. Related bug is tdf#44282.