P: Custom Order lost with slight accidental movement of thumbnail in filmstrip

I find the last couple of comments intriguing. 

We've never reliably reproduced this behavior in testing. Have any of you disconnected your Wacom tablet and then been able to reproduce this - or is it only reproducible with the tablet attached?

It is hard to believe that such a simple and widespread issue has not been resolved after so many years of users having to struggle with this handicap

I have to say I rarely use a tablet and it happens when using the mouse, sadly I have to keep using Lightroom for another year due to a long term project. After that I'm done with it, as much as I like it the problem is nearly constant. I've tried alternative software and some of them are more than viable

I think you are right, in that the Wacom tablet may have a contributing part to this infuriating issue.  I have come to this conclusion having read many years worth of comments on the matter.  And I have never used a mouse on my iMac, and always had the problem with Lightroom viewing order

I would have thought it is a simple matter for Adobe to strengthen the choices of viewing order, or simply offering a lock for a particular choice of viewing order, which could be toggled on or off if a change in order is required

Rectifying this issue would save hours and hours for many people during photo editing (post shoot production)

Otherwise, time to look for other photo editing software

I have experienced this off and on for a while.  I can say with confidence that it has to do with the Wacom tablet I have.  The tablet is a new tool for me.  Before, when only using a mouse, the sort order when returning to Photoshop would switch to custom from capture time only if I would change the order of the images before sending the image to Photoshop.  If you move an image around in Lightroom, it automatically changes the sort order to custom.  At least this is my experience.

Now, with the tablet, it has happened most of the time and driving me nuts.  The pen/tablet interface is quite sensitive.  I am having a hard time getting used to the tablet because of this in the first place.  What I believe is happening is when touching the image in lightroom, it moves slightly, perhaps imperceptably, but doesn't actually change the order of the images.  Lightroom, however, see the slight move as an order change and switches the order to custom.  When I go back to using the mouse, the sort order doesn't change.  When I use the pen, it does.

Turning off Lightroom automatically changing to custom order would fix this problem.

The problem also appears, although not consistently, when sorting using ratings in develop module on my last pass to straighten the one's I'm going to export.  I had been sorting, straightening and then turning the sort off after switching to the library module (selecting "None" at the top of the collection window) and that's when I would notice the change to Custom.  I've found that if I turn the filter off with the "switch" before leaving the develop module, it doesn't appear to happen any more.  No external editing tool was used.

i use wacom too 

yup me too

Add me to the list too. I've also had this issue for a few years now. Across new computers and fresh installs of Lightroom and PS. My workflow is to star the images I want to keep and work on. I've never tracked the percentage that this happens but I would say at least 50%. 

This is not a side issue - it is a main issue.  And will lose Adobe customers.  Why have they not resolved this issue now - it has been a problem for many many years, and hinders a myriad of users