Label not updated if triggered from user interaction with another layer

[DelazJ]

What is the bug or the crash?

I'm trying to update the label of a layer depending on selected features on another layer, based on their spatial relationship. The map canvas refreshes automatically only if both layers are labeled.

Steps to reproduce the issue

Let's take two layers, "commune" and "region", that have features overlapping. And I want to label "region" depending on whether an overlapped "commune" is selected. I'm using:

with_variable(
  'containedcommunes'
  overlay_contains('commune', @feature)
  case
    when array_contains(array_foreach(@containedcommunes, is_selected('commune', @element)), 'true')
    then "nom_officiel"
    else "code_siren"
  end
)

When I select a feature in "commune":

• if the commune layer has labeling enabled, the region's label changes as soon as I do the selection. The expression used for commune doesn't matter.
• If commune layer is not labeled, the region's label doesn't change unless I pan/zoom/refresh somehow the canvas.
• If another layer in the project is labeled, the region's label doesn't change either unless I pan/zoom/refresh somehow the canvas

Versions

Tested on Windows 10 with QGIS 3.41 98c5bf8

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[nyalldawson]

You need to setup the layer dependencies for things like this to work -- implicit dependencies from expressions are not automatically considered.

[DelazJ]

Oh, YESSSS! I forgot that tab. Thanks a lot, Nyall.