These used to behave differently in the tree. A single instance datasource (or configsource etc.) would not have any children. If you wanted to see the data associated with that module under a device, you simply selected the module. In UIv4, you have to expand the module to show the one, singular instance under it and then click again to select it. This adds an extra click when navigating. This extra click has been avoided in the past by LM as a matter of policy (how many modules are in the “ungrouped” group to avoid adding another click to get to the data?).
Also, now that multi-instance and single instance modules both have to be expanded to show the children/child, the new distinctive icon that tells you a module is multi-instance (circle with the letter M in it) makes no sense. Essentially everything acts like a multi-instance datasource. Since that’s the case, why call out the difference? In one way (adding the click) LM removed the distinction between single and multi. In the other way, they added another distinction between the two. To what purpose?
Also, by having multi-instance datasources show up with an M instead of a D, the distinction there is also lost. Is it a datasource or a module? Does the M stand for module? Why doesn’t it just show a D?