Gap between the leader underline and the tab.

[VBL2]

Why does the UNDERLINE LEADER applied to a tab, not go completely to the tab? In the proofing process of a form, it always gets flagged as an error. It's very annoying and hard to explain to editors and requires timely workarounds. 

[Thunder-Lightning]

The length of the leader is multiple of the Underline character in your case.

You can create adjust the length by adjusting the horizontal scale of the Tab character.

You could then create a character style with the horizontal scale. In your paragraph style, add a GREP Style to apply that character style to the Tab character.

[rob day · Accepted solution]

Hi @VBL2 , You might get a better alignment if the final tab is set as a Right Indent Tab:

Leader glyphs are designed to line up vertically, which is more obvious when you use a dot character—Leaders always create some variable spacing before and after the Tab.

If you don‘t care about the vertical alignment of Leader glyphs, use an Underline applied to the tab. Something like this:

An underlined tab character could be handled with a Nested Paragraph Style:

[VBL2]

thanks, Rob, I appreciate your insight. I'll give this method a try.