As can be seen on the first image there are outlines around the brackets and parenthesis (blue and red colored), on the second picture is shown what happens to these outlines if I move away to another line ready to type. The blue boxes become solid black and the red become dotted black, but they are still there. They annoy me immensely and I would be grateful if someone would show me how to remove these box highlightings.
I found the answer myself. These boxes are called placeholders. They can be removed by going to Options > Configure TexStudio. Then on the bottom left check Show Advanced Options. Go to the Completion tab on the left and in this tab uncheck Arguments as Placeholders on the top right. See the attached image.
The boxes are placeholders. You can navigate between them using
They vanish, if you type over them e.g. if the cursor is before a closing bracket placeholder
) will move the cursor past and remove the placeholder.
You can also use
Idefix -> Remove Placeholder (Ctrl+Shift+K).