If this check box is selected, tab characters are used:
On pressing the Tab key
For code reformatting
When the check box is cleared, PhpStorm uses spaces instead of tabs.
If this check box is selected, the part of indentation defined by the nesting of code blocks, is made of the tabs and (if necessary) spaces, while the part of indentation defined by the alignment is made only of spaces.
If this check box is cleared, only tabs are used. This means that a group of spaces that fits the specified tab size is automatically replaced with a tab, which may result in breaking fine alignment.
The Smart Tabs check box is available if the Use Tab Character check box is selected.
In this text box, specify the number of spaces included in a tab.
In this text box, specify the number of spaces (or tabs if the Use Tab Character check box is selected) to be inserted for each indent level.