Hello
According to me (as it is in LO and as far as I remember in MSO), when I use the style cloning tool in the beginning of a line, the whole line should change style.
In the case bellow, the style is only partially applied.
It looks like a bug to me.
The file:
leçons calcul mental.docx (131.3 KB)
Hello @arcqus
You are using this tool incorrectly. To actually apply the copied style you need to select the range that must be transformed:
Pretty much the same behavior in MSO.
IMHO, it should do nothing if I’m using it incorrectly.
I checked MSO online, and yes, it is working the same as OO (but I clearly remember having worked this way in older version of MSO).
But, I’m not crazy 
and others see the things the same way as me , since:
in google docs, it working like this:
In LO it is also working like this:
The logic is (the way I see it) that if you click the beginning of a line, you want the style to be applied to the whole line. From a user standpoint, it is more efficient than selecting the whole line.
I understand. Desktop Editor work in the same way for the case you’ve described above. However, initial file has different use case, in which style is located in the separate section. As I mentioned, Word acts exactly like Desktop Editor with initial file.
Indeed, I’ve checked that.
Here I am discovering something.
How & where can I see that ?
How can I change that ?
Many thanks !
After digging a little the feature I think I was wrong about the section. It seems to be related to formatting that is already set up in the document. You see, styles represent several properties of paragraph and text (e.g. font, font size, etc) and when some styles are applied, they do not seem to have a directive to overwrite certain properties (seems to be a default practice, but cannot tell for sure). So when applying a copied style to a paragraph/text that already has formatting, it may skip some properties, hence will apply style only partially. This also explains why it works in the new document in which none of the formatting is applied.
Technically, I was right about saying that the tool was used incorrectly as if you want to overwrite all properties of current style with properties of the copied style, then you need to select all text/paragraph you’d like to format.
Unfortunately, this is some “behind the scene” processing. Not sure if it can be checked directly.
I found simple solution to this. You can simply reset formatting of the whole document to make sure that none of the custom formatting is applied by selecting all content with CTRL + A and then resetting formatting with CTRL + Spacebar. This will allow you to apply copied style just as expected:
Hi @Constantine
As I say to my pupils, “it’s not because the others do this that you have to do it” 
To be more serious,
When I was working in the software industry, I tried this kind of answer with my unhappy users, however it was rarely heard
I’ll just select the whole line and apply the style, it will be faster.
Thanks for having dug this subject.
It’s not that simple, I’m afraid, as there are standards in the industry.
I understand. Maybe I am not completely certain why styles are like that in the document, but still I am sure that they are causing this behavior and the editor actually reacts accordingly to that.
I hope it was useful at least. Should I close the topic as solved?
Let’s rock them
Yes, as always !
Yes, thanks again for your time.