Trigger listeners when modifying element Observable{Matrix}

General Usage
1

If I create an Observable{Matrix} :

X = Observable(rand(3, 3))

and that I have some listeners on X

a = @lift sum($X)
5.7....

Is there any way for this listener to be triggered when I only modify values of X:

X[][1, 2] = 3.0
a[]
5.7...

The only solution I found was to put an additional trigger:

trigger = Observable(true)
a = @lift sum($X) * $trigger
X[][1, 2] = 3.0
trigger[] = true
a[]
8.11....
2

Before you’d often see

array_observable[][1] = rand()
array_observable[] = array_observable[]

but I prefer the more explicit

array_observable[][1] = rand()
notify(array_observable)
3

Thanks! I was not aware of notify!