*Steps to reproduce:*
# Open the linked Git Project
# Navigate to Window > Rendering > Lighting
# If there's no Lighting Settings Asset create one and assign it
# Scroll down to the "Lightmap Packing" section and set it to "Custom"
# Set "Packing Method" to "XAtlas"
# Generate Lighting

*Actual results:* Editor processes start with the "Hold On" "LightingWindow.MouseUp" and takes ~20 minutes until the Generation appears in Background Processes, cancelling the also takes ~20 minutes
With the "Packing Method" set to "Unity" it takes ~1 minute until the pop up disappears and Generation can be cancelled, cancelling is almost immediate

*Expected results:* Users should be able to cancel Lighting Generation if the process takes too long and users shouldn't be locked in to a process for a long time, if this is expected cause of the new Packing Method there should be some sort of indications to the user why it's taking so long, not only that a process is ongoing for UI

*Reproducible with versions:* 6000.3.0b1

*Can’t test with versions:* 2022.3.66f1, 6000.0.56f1, 6000.1.16f1, 6000.2.0b4 (No XAtlas Feature)

*Tested on (OS):* Windows 11