In a style I have defined:
one tab "right alignment" 45 mm
another tab "Left alignment" to 47 mm
The text is justified in this paragraph.
Effect (the tabs are typed instead of '_', the spaces following the '_' are not captured):
_ bar bla bla bla :_ blabla ...
_ foo blabla :_ bla bla blabla...
The 45 mm tab is intended to align the ":" character.
The 47 mm tab aligns the first character after the ":".
When the text after the ':' spans multiple lines, the ':' are no longer located at 45 mm and the following first character is no longer located at 47 mm.

Only if the paragraph is "left aligned", everything works alright.