SYMPTOM:
As described in KB39823: New Feature in 9.3.0 MicroStrategy Web: Export Single Grid/Graph off a Dashboard, the functionality in Web version 9.3.0 has been enhanced to incorporate a facility to export individual grids or graphs to Excel or PDF with a single click.
In Flash view, this feature is available on mouse-over:

Is it possible to deactivate the display of this icon?
CAUSE:
This is currently behaving as designed. This icon is currently displayed by default in Flash mode and it is not possible to disable this in Strategy Web 9.3.0.
ACTION:
The ability to hide/display the icon has been addressed in Strategy Web 9.3.1. Update to this version to take advantage of the fix.
Refer KB43994 for more information.
KB41627