Theme Boost. This is not an issue in Classic theme. This issue is only happening when editing question.

1.Create new or edit existing drag and drop onto image question

2.Position draggable items onto image, see screenshot (draggable items) 

3.Note drop zones coordinates

4.Hide left navigation panel, see screenshot (draggable items moved left)

5.Confirm that drop zones stays same.

6.The draggable items appeared to be out of image

The hidding/showing left navigation panel is not affecting draggable items positioning, when attempting quiz 

1. Save question from previous steps
2. Create quiz and add this, d&d onto image question to the quiz
3. Attempt the quiz
4. Start answering this question by placing draggable items onto the image, see screenshot (attempting quiz)
5. Hide left navigation panel
6. Confirm that draggable items are positioned correctly, adjusting to the image , properly, see screenshot (hidden left panel_when attempting quiz

Can also be reproduced at https://qa.moodledemo.net/question/question.php?cmid=31&id=50

Note: drag-drop markers qtype not affected.