#385021
I think the slowdown is caused by the blocked emitters UI, which needs to look at all the objects in the scene to determine which ones have emitter materials applied, so it can populate the lists. However, I've made a test with 8000 objects and several materials and I didn't get a noticeable delay when opening the properties window, so maybe there's another factor involved besides object and material counts. It would be helpful if you could send me a scene where the slowdown is obvious, so I can confirm that the blocked emitters section is the culprit.

Anyway, we will move that part of the UI into a separate dialog which opens when you click a button, so you only have to wait for it to load when you actually need to manipulate the emitter lists, not every time you need to access object properties.
#385189
Thank you for the scene, it helped me identify a second cause for the problem: referenced materials. When the plug-in scans the scene looking for emitter materials, if it encounters a referenced MXM material, it has to load it to check if it contains emitters. This obviously takes time if you have lots of MXM references. I've made it a bit more efficient now, but unfortunately it cannot be avoided. However, moving the light linking UI in a separate dialog will ensure that the materials are only read when you need to use that functionality, so the object properties dialog will no longer show the slow down.
#385289
I've uploaded a new version to the early builds site. Please give it a try and let me know if the properties window is faster now. I haven't had time to separate the light linking UI into a new dialog, I'll do that in the next update.
#385394
Sorry Mihnea, I missed your post and the update until now. I've tested the new version with the scene I'm working on at this moment. It's pretty similar to the one I sent you; with 350 objects, 7 light sources (3 mxi emitters and 4 regular ones) and 79 materials. I still notice some delay though. If it opens faster now it wasn't a big improvement (maybe because it's not really crowded with objects and materials). Probably the change in the light linking UI will be the key in this case.

Cheers!
Will there be a Maxwell Render 6 ?

Let's be realistic. What's left of NL is only milk[…]