1332896 - If none of the sub-items of a pulldown-(sub-)menu are enabled, the (sub-)menu itself should be disabled

Status: UNCONFIRMED

(SeaMonkey :: UI Design, enhancement)

Description

[Rainer Bielefeld]

This one is a spin off from "Bug 241213 - Message window for .EML file needs working commands" - see i)!
Steps how to reproduce with Server-Installation of  official  en-US SeaMonkey 2.50a1 (NT 6.1; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0 Build 20170110004313  (Default Classic Theme) on German WIN7 64bit:

0. Download  Attachment 8826695 [details] for Bug 1331042
1. Launch Email Client
2. Menu 'File → Open File → Browse for "ThisIsAtestEmailFor_emlImport.eml"
   and open
   » File opens in new separate window
3. Menu 'Message → Go → Try to find a working pulldown menu item'
   Expected: Something can be done
   Actual: nothing can be done:
           Go → Back                 ; disabled
           Go → Forward              ; disabled
           Go → Next →               ; All Submenu items are disabled
           Go → Previous →           ; All Submenu items are disabled

a) If there is nothing what can be done because
   all items of level(s) below are disabled, the root item also should
   be in "disabled" design to spare unsuccessful attempts to find
   something what will work for users
b) for the example that means
b1) 'Next' and 'Previous' should be in disabled design, because all
    submenu items also are disabled
b2) 'Go' menu item should be in  disabled design, because all
    submenu items also are disabled

Comment 1

[Rainer Bielefeld]

c) Some similar Bugs found with <https://bugzilla.mozilla.org/buglist.cgi?cmdtype=dorem&remaction=run&namedcmd=DUPs1332896&sharer_id=41036> 
   like Bug 973861, Bug 635674, Bug 339602

Comment 2

[Frank-Rainer Grahl (:frg)]

I think a general fix can't be done in SeaMonkey (maybe with some listeners but not sure) but would need a change in Gecko. Probably faster to just fix the places where you notice it.

Comment 3

[Rainer Bielefeld]

(In reply to Frank-Rainer Grahl from comment #2)
I think so, too. 

I wonder whether there is a general style guide. At least 1 Esample I fine (menu 'Message → Attachments' does not show the lower level pulldown items if no attachments are available. Is that optimum (for pulldown items I think so) or should the possible items be shown greyed?