Yellow Background on a Glyph

I have some glyphs im my font that are highlighted in yellow when I type them out in the program. They also behave strangely when I click (randomly disappearing, changing places with others, stuff like that)

What does it mean?

Can you post a screen shot?

The only thing I can think of it that you somehow switch to the background mode (cmd+B).

Here is a picture.

The highlight dissapears when I type another glyph behind it.

When I try to position my cursor behind the glyph, the window freezes and I have to click somewhere outside the program and back into the window to make it continue.

Is that a grave accent?

OS X does that when it is waiting for the letter to put under your combining mark. This is not limited to Glyphs.

Oops. You are right. How embarrasing. Well I guess that’s one problem out of the way…!