Dashboard object with conditional formatting. To hide or make grey the object on the dashboard depends on conditions?

This is possible through an XFBR rule. Something like this should work:
Else If args.FunctionName.XFEqualsIgnoreCase(""ButtonVisible"") Then
'Pull in the workflow time
Dim wfTime As String = args.SubstVarSourceInfo.WFTime
'Check the condition and return the format value
If wfTime.XFContainsgnoreCase(""Jan"") Then
Return ""IsVisible = False""
Else
Return ""IsVisible = True""
Then, you call the rule in the Button Component format property:
End If