Follow-up from bug 411849:
Investigate unconditional removal of 'disabled' state in function changeContextMenuForTask(aEvent) in calendar/base/content/calendar-task-tree.js:
Opening context menu on todo panel of todaypane with no tasks selected (e.g. just after Thunderbird has started), the function 'applyAttributeToMenuChildren'  called inside changeContextMenuForTask ,
sets all popup menu items with a "command" attribute to 'disabled' state, but 'New Task ..." item, i.e. "calendar_new_todo_command", must be enabled to allow to create a new task, so the code lines 111 and 112 in calendar-task-tree.js file remove the disabled state for new_todo_command that must be the only enabled command when no task is selected.
Might it be the right answer?
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:188.8.131.52pre) Gecko/20090826 Calendar/1.0pre
Doesn't seem correct, at least in the following case: All calendars are read-only or switched off. Opening the context menu enables the New Task menu entry and New Task toolbar button although it is not possible to create a new task.
Confirmed as bug per comment#2.
Created attachment 401818 [details] [diff] [review]
(In reply to comment #2)
> Doesn't seem correct, at least in the following case: All calendars are
> read-only or switched off. Opening the context menu enables the New Task menu
> entry and New Task toolbar button although it is not possible to create a new
Therefore, basically, it should be checked only the enabled state of the commands "calendar_new_todo_command" and "calendar_new_todo_todaypane_command".
I tried this patch with enable/disable/read-only/writable calendars and with a calendar that doesn't support tasks (Google Calendar + Google Provider), and it seems working in every case.
I'm not completely sure whether 'removeAttribute(disabled)' is the same of 'setAttribute("disabled", false)'. If not, can be used a 'if-else' statement with both 'removalAttribute' and 'setAttribute'.
Comment on attachment 401818 [details] [diff] [review]
>+ let newTodoEnabled = calendarController.isCommandEnabled("calendar_new_todo_command") &&
>+ document.getElementById("calendar_new_todo_command").setAttribute("disabled", !newTodoEnabled);
>+ document.getElementById("calendar_new_todo_todaypane_command").setAttribute("disabled", !newTodoEnabled);
setAttribute doesn't take a boolean as a second argument, but a string, so you need to setAttribute/removeAttribute there. You could do setAttribute("x", "false"), but its more common to remove the attribute.
Please see our helper in calendar-ui-utils.js. We have setBooleanAttribute, but I just say its using "true"/"false" too. The other possibility is
setElementValue("calendar_new_todo_todaypane_command", !newTodoEnabled && "true", "disabled");
(or similar, please doublecheck). Setting the second parameter to boolean false (=== comparison) causes the attribute to be removed.
codewise r+ with that changed, please upload a new patch.
Created attachment 401853 [details] [diff] [review]
(In reply to comment #5)
> setAttribute doesn't take a boolean as a second argument, but a string, so you
> need to setAttribute/removeAttribute there. You could do setAttribute("x",
> "false"), but its more common to remove the attribute.
Here the difference. Sorry for that and thanks for your explanation.
In my defence (;-)) I have to say that before doing the patch I checked the "setAttribute" function on calendar code (by mxr) and aside from "false" and "true" arguments, I found a lot of setAttribute("disabled", true/false) or even cases with variables as second argument.
I've done in the more common way by removing the attribute when it should be disabled.
Since "patch-v2" has changes request in comment #5, I don't think it needs another review.
Sorry for the late checkin, forgot about this one!
Pushed to comm-central <http://hg.mozilla.org/comm-central/rev/5b06b0538127>