My notebookbar has no icons

Hi, It is the first time I am having my notebookbar without icons. I searched but there seemed to be no reference to it.

Here is its image

Please help me to fix it.

Similar problem here. My icons disappear when I open the print preview, but only when notebookbar is in contextual single, groupedbar full or groupedbar compact mode. Even after I’ve returned to editing my document the icons are still missing. Icons can be restored by changing the view mode of the notebookbar but this isn’t a ral solution.