Cannot remove background colour in some slides

Hi all,

In a eLearning one of my colleagues created, in some slides there's a yellow background colour if you check it in preview, however the background colour of the slide is set to white and the player background colour is also white. I checked the slide master and that's a blank slide (and have reset it , just in case). Nothing helps... any other idea where that colour setting can be hidden ?

Thank you so much!

5 Replies