When i pressing 'space' in keyboard on some folder in TC is show me the size of the folder with files inside, i mean TC do this without DirSizeCalc plugin installed.
When installing DirSizeCalc is still the same. My question is what exactly DirSizeCalc do?
You must be more explicit what exactly of the fine manual you didn't unterstand.
"Since there are many things which have never happened and never will happen,
and which nevertheless are clearly conceivable, and imply no contradiction,
how can one say they are absolutely impossible?" Leibniz
2Xtrician
If you have a more specific qquestion which isn't answered in the documentation don't hesitate to ask. As the documentation is relatively new there might be still still important scenarios which are not covered.