No Longer Able to Color Horizontal Line

Outlook Express 6

Up until a couple months ago I was able to insert a horizontal line and
also 
color it.
Example:

Type a sentence.
[Insert] horizontal "line"
 -----------------------
Type "second" sentence.
Old ability:
1) Highlight "line" above. Change font color to blue.
2) Click on inserted horizontal line above "---------". Change font color
to 
red.
3) Highlight "second" above. Change font color to green.
Current ability:
Can only do steps 1 and 3 above.
When I click on the horizonal line, the icon for changing colors "greys
out" 
and is not accessible for use.
All I can think of is that I've somehow accidently checked or unchecked a 
"check box".