AutoCAD Civil 3D

[#1]

I'm trying to edit MTEXT boxes that I've created and when I begin the edit (delete/add text, change font size, etc.) the text box disappears until I click "OK" essentially making me do my edits blindly.  After I click OK and return to model or paper space, the text box reappears and my edit has been made.

Never seen this happen before... any thoughts what's going on?

Thank you.

[#2]

Check the layer of the text you are editing and well as your current layer.

If one has a linetype that  is set to something like a fence line, or other custom linetype, this could cause it to happen.

Other things to check... was this drawing from a previous version that was just opened and saved your newer format?

Is Layer 0 frozen?

I'm sure there could be more things to check, but this is a start. 

[#3]

You nailed it... the line type needed to be adjusted. Thanks so much.