When i make a text box and start typing a grey line appers in the middle of my text, any ideas on how to get rid of this grey line?
Check the applied paragraph style (paragraph formatting) and/or character style (character formatting) for "Strikethrough Options". Could also be "Underline Options".
A screenshot of your case would help.
Enable "Show Hidden Characters" in InDesign before taking the screenshot.
The forum software allows you to place the screenshot by using the small camera icon (Insert Image) at the top of the editing field.
Many thanks, sorted.