Precondition:
‘Host 1’ - with items / item prototypes
‘Host 2’ - without items / item prototypes
‘Host 3’ - without items, but with item prototypes

Steps to reproduce:
1. Add Simple graph to screen and click ‘Item’ button
Result: In popup displayed hosts with items (‘Host 1’)
2. Add Simple graph prototype and click ‘Item’ button
Result: In popup displayed all hosts
Expected: In popup displayed only hosts with item prototype ( ‘Host 1’, ‘Host 3’)

This screen behaviour can affect to Simple graph prototype widget development.