Why is \vec{} underlined in red in LaTeX drafts?

[Janosh89]

Can anyone help? What is the convention for inserting the vector symbol?
I have a draft with -(\vec{2.5})^2 which displays correctly in preview
$-(\vec{2.5})^2\\$
why is vec troublesome and underlined in red?? Should I ignore!
I realize that I'm not using a variable.

 

[Mark44]

Can anyone help? What is the convention for inserting the vector symbol?
I have a draft with -(\vec{2.5})^2 which displays correctly in preview
$-(\vec{2.5})^2\\$
why is vec troublesome and underlined in red?? Should I ignore!
I realize that I'm not using a variable.

What you have is how this command is used. I don't see any red underlining.

$\vec x$ - Raw script \vec x
$\vec {x_1}$ - Raw script \vec{x_1}
The braces, { }, used in the 2nd example are not required in this and most other commands when what follows the command is a single character. If there are two or more characters, you have to use braces to indicate what is included.

Before anyone else jumps into comment about 2.5 not being a vector, this post is about LaTeX use, not vectors per se.

 

[Janosh89]

Thanks for the full description, Mark44

 

[FactChecker]

The red underlining is probably the spellchecker doing that in the editor. Those are not very sophisticated when it comes to anything that is not a word of the English language.