You may have noticed that in Preview and your released content that your text is highlighted with a colored border when selected:
...this is an accessibility highlight that is provided by default so that users who are visually impaired will be able to locate on screen where their screen reader is currently focussing on.
For the most accessible content we highly recommend leaving this feature on.
If you wish to remove this highlight from your course, it is possible to do so via your Project's Style.
In the Style choose 'Advanced Options' - this will expand the available tabs in your Style
Scroll to the bottom of the page and you will see the 'Button Focus Outline' options:
...set the width of the outline to 0px and select 'Solid' from outline style dropdown:
...and press 'Save Changes'.