How to set columns for "This PC" -only-?

This probably sounds like (or like is) a newbie question.
However, sorry to say, but setting columns / folder formats / layout has always been a bit confusing for me and often I manage to mess things up.

Already for quite some time things has been set the way I want and I don't want those to be changed, except the layout/columns of "This PC" .

Currently it shows filename and size in bytes.
I'd like to have filename, size (auto), free space (auto) and percent free (auto).
Change to apply ONLY for "This PC".

How to set this?

Thanks.

You're almost there. Just click OK in the Save Folder Format dialog. (It should show "This PC" as the path you're saving for, but doesn't. That's a bug, but it still works and saves the format for that folder.)

You can also edit the same thing via Preferences:

Thanks Leo.

After saving other layouts changed: I lost columns like extension, path length, folder path.

Also note that in "This PC" though not selected, after clicking Save this folder format, kb size was added.

FWIW I have added some screenshots. As it is too much for the forum, I have created a rar file.
Could restore Opus to the previous situation as I always make a backup just before applying whatever changes to Opus.

Opus-changing columns of ThisPC.rar (334.9 KB)

After making the change, close the window and test in a new one. Does that make a difference?

If not, something else must've happened to change the format for normal folders. Inspect the formats in Preferences to see what's what.

Or you might have the Format Lock turned on (can't see the status bar in the screenshots).

Yes, the folder format is locked, for all folders. The padlock at the right, in the status bar, is closed.
This I did because I didn't want things to change. I was hoping that whatever I did this format/layout wouldn't change. Never. But one way or the other it still seems possible by changing the "This PC" columns.

FWIW - here the Preferences -> Folder Formats screen

The format lock should be off normally. The format will only change if your saved formats tell it to change. You don't need to turn it on, and if you do it will cause problems like this.

Only turn it on when you want to override your saved formats.

Thanks again. I have just unlocked folder format and indeed notice the layout (i.e. columns) do not change. It is my lack of knowledge on this but I genuinely thought that I needed to have the format lock set to ON (reading the Help-file) in order to keep the format, no matter what I change elsewhere (in this case 'This PC').

BTW - screenshots number 4 and 5 (in the RAR file) you will see that after saving the format (This PC) the kb column is added. Could you reproduce that? Is that a bug?
Within the same 'Save Format' panel, the kb column is not visible. However, it is visible when you r-click on the columns and then select 'More...'

The Locking the Format article in the Manual includes this paragraph:

Opus therefore lets you lock the format in the file display. When the format is locked, automatic changes to the format are disabled - the display format won't change at all as you navigate from one folder to another, unless you manually change it using the Folder Options dialog.

That part seems very clear. Was there another part of the manual that made you think the format lock did the opposite of what it really does?