Thanks for info it suppose to disappear last. Tried on 1080p monitor, also notice easily missing in VR at zoom level larger than 14 (LNM from webserver) not sure because of what reason (canvas size?)
At map level where trail disappear, changing to "Default Map Detail" or "More Map Detail" or "Less Map Detail" will not let the trail show again.
The trail itself is very long around 1300km (Beijing to Harbin), other shorter trail doesn't show the same behavior at that same zoom level, there is no indicator which zoom level i am at, but it seem 7 from minimum.
I am importing it from google map direction into GPX format, then append as aircraft trail to guide me as I fly, but found out when i zoom in it just disappear.
Keep up the good work on Little Navmap.