Customize a toolbar in Draw, e.g. add the command 'Extended Tips' from category 'Application'.
After adding the command, click on Modify in the Customize dialog.
Click on 'Change Icon'.
Click on 'Import' and select a selfmade icon.
Assign the icon to the newly added command.
Make sure the command has got the icon.
Close the module and start another module.
Customize a toolbar with the same command as in Draw.
Notice, that the command has no icon, although an icon was assigned in Draw.
Open customize dialog again, select the command, click on 'Modify' and then on 'Change Icon'.
Scroll the list.
Notice, that your selfmade icon it not only not assigned, but is missing in the list.
Request: Each icon, that has been imported and assigned to an .uno:command should be available in each module without need to import is again.
(In reply to Regina Henschel from comment #0)
> Request: Each icon, that has been imported and assigned to an .uno:command
> should be available in each module without need to import is again.
this issue is inherited from OOo.
each module has it's own icon setup to choose from... even the default icons are not all available across different modules.
and I confirm a custom icons has to be imported in each module in order to be freely selectable