Change Codeblocks line number background and foreground back to its default colors

If background and foreground of line numbers did not change back to its default colors, go to 

Menu > Settings > Environment > Colors

Category > select: Editor

Click the “Default rectangle color at the right panel” for each of the following. 

* editor-caret

* line number background color

* line number foreground number 

* margin chrome color

* margin chrome highlight color

Click the button OK to close the dialog window.