[Bug] insert spaces instead of tabs

[adminka-root]

The function does not work correctly. Actions:

1. Select all contents of one line
2. Press "tab" twice

Expectation: The line will be double indented, preserving the contents of the line. Reality: a double indent appears before the line, but the contents of the line are deleted.

The same behavior is observed, for example, in the Xed text editor. However, I don't think this is normal. After all, if you disable the function of replacing tabs on spaces, then everything works correctly (that is, with saving the contents of the line).