How to restore one line taskbar?

[rostek2]

I accidentally (I have no idea how) clicked on the taskbar and suddenly it became double in size.

There is no option to reduce it to one line like I had before.

Anyone know how to change this back?

Reducing the taskbar using the cursor does not work.
What is the most funny - I can do it much bigger - for example the size of 3,4,5,7 lines - but can't decrease its size to 1 line.

[rostek2]

It looks that somehow date settings have changed as before I had only time. Now day and date was added and that's why the size of the taskbar was extended by additional line.

[rostek2]

OK - Done.
I've moved between quick launchbar and taskbar running applications and now I have one line taskbar.
I don't know but it looks like a bug. It should be corrected.