Affects:
* Windows 10, 64-bit
* BOINC 7.14.2 and many previous versions
* Installed as a program, not a Windows service
* Any project or projects

Observed behavior:
* While selecting a range of tasks with the same status, the set of user-selected tasks (UST) becomes -- on its own -- discontinuous. One or more User-Selected Tasks (UST) become unselected, randomly. (Randomly, in the sense that BOINC "chooses" which tasks to unselect.)

Usually or maybe always:
* Tasks not selected by the user may become selected by BOINC, "randomly." (as above)

Possibly:
* The number of selected tasks remains the same. That is, for each UST that BOINC "chooses" to unselect, another user-unselected task (UnUST?) is "chosen" by BOINC to select.
* It only occurs when BOINC has been running continuously for a long time. (This unwanted behavior occurs often, yet now that I've re-started BOINC, and I'm trying to get the behavior to occur, I have been unable to.)
* It only occurs rarely.
* It only occurs when selecting tasks in a certain manner, and not in all possible manners:
- mouse only -- click-drag-release
- combination of mouse and keyboard -- shift-click on list
(It might happen also with keyboard only, but I don't do that often. -- shift-down-down-down-down-down)
* It only occurs when tasks are sorted by a certain field.
* It only occurs when a large enough group of tasks are selected

Example:

Task 1 Running
Task 2 Running
Task 3 Task suspended by user
Task 4 Ready to start
Task 5 Ready to start
Task 6 Ready to start
Task 7 Ready to start
A. User selects tasks 5-7.
B. For a split second, User confirms (visually) that tasks 5, 6 and 7 are selected, and that no other tasks are selected.
C. Instantaneously, and despite no further input from User, the selected tasks are now: 3, 5 and 7. The Suspend button is gray (inactive), since 3 is now selected.

This sort of thing probably happens 0-5 times a month, 15-35 times a year.

I have only seen this behavior with BOINC, and not with any other program. Nor have I seen any behavior in other programs that would lead me to suspect, for example, that it has to do with low mouse battery, or anything else. The tasks are selected, and almost instantly change on their own. I'm not fast enough with my mouse to unselect certain tasks and select others outside my selected range, and besides, sometimes tasks on prior or following pages (off the screen) get BOINC-selected. And I'd have to be holding down Ctrl key to do that.

Forgive me if I've posted this before. It's been a problem with BOINC for a long time.

---

Anything to do with the button in the Tasks tab: "Show all tasks / Show active tasks"?

I use multi-select quite a lot (usually mouse-click, shift-click at end of a range, ctrl-click to add or remove single tasks). I've never seen this problem.

Wild thought - do you have the tasks displayed in any special sort order? I'm careful to keep all my displays in 'natural' (FIFO) order.

Thanks for responses. I welcome more.

Anything to do with the button in the Tasks tab: "Show all tasks / Show active tasks"?

Les, I've not used "Show active tasks" (much? at all?). That's handy. Thanks for bringing it to my attention.

I use multi-select quite a lot (usually mouse-click, shift-click at end of a range, ctrl-click to add or remove single tasks). I've never seen this problem.

Wild thought - do you have the tasks displayed in any special sort order? I'm careful to keep all my displays in 'natural' (FIFO) order.

Richard, only rarely do I use multi-select. My typical order is by Deadline.

Some other thoughts:

* I have a Rainmeter skin running on screen, on top. Could that be it?

* I should re-install BOINC on my laptop, to see if it ever happens there. (Nervous about BOINC reducing its lifespan.)

* When I came back to my PC this morning, the set of tasks I'd selected yesterday were discontinuous. I've now set World Community Grid--one of my 3 projects--to "Won't get new tasks." I'll select some WCG tasks and leave it alone for a day or two and see what happens. If nothing else, I'd like to nail down some of my "Possibly's."

* I should get a corded mouse, too. I don't THINK that has anything to do with it, but...

I thought for sure I wasn't alone in this, that others were having this, too. I've just been putting up with it since I first learned about BOINC in 2016.

Since my tasks are almost always sorted by Deadline, if I'm selecting tasks at the precise moment BOINC is downloading others, they could be inserted into the list as unselected tasks. But here's why I don't think that's what's going on:

1. The list of tasks doesn't lengthen. I don't want to say NEVER, but if I selected 10 tasks, and BOINC downloaded 3 tasks with a deadline in the middle of my 10 tasks, then the list would lengthen to 13. This doesn't ((hardly) ever) happen.

2. It's typically 1 - 3 odd tasks that are deselected by BOINC, not a bunch, as usually download together.

3. The deselected tasks (if plural) are themselves ((almost) always) discontinuous. Tasks that download together usually have the same or very similar deadline.

Summary:
I got the PC to repeat this behavior by leaving it alone for hours with 10 tasks selected.

Details:
After my last post, I selected 10 WCG tasks. All "Task suspended by user" with deadlines on the same day (2/23/2020), 4:31:01 AM to 7:57:11 AM from the same project (Mapping Cancer Markers 7.41). I'd already modified Project WCG to "Won't accept new tasks."

As of 40 minutes ago, only 5 of 10 were still selected. Numbers 5, 6, 7, 9 and 10.

BOINC had selected on its own 2 new tasks. They were WCG tasks for Microbiome Immunity Project 7.16, with deadlines on 2/26/2020. In between were dozens of Asteroids@home tasks, all due 2/23/2020 4:40:xx PM.

I'd checked the PC a couple times this morning, and all 10 tasks were still selected. So it happened sometime in the prior 1.5 to 2 hours.

Only Chrome 80.0.3987.106 (Official Build) (64-bit) and CCleaner* 5.63.7540 were running with BOINC 7.14.2. Rainmeter skin was off / unloaded. Chrome had 20 tabs running. Probably <40% of RAM was in use. * The windows tray icon of CCleaner, not the full program.

Conclusions:
So, that answers some questions, or suggests some answers:
* How often does it occur?
* Does the total number of selected tasks remain the same? No.
* Does it only occur when BOINC has been running for a long time? No. I'd restarted BOINC this morning.
* It doesn't only occur instantaneously upon selecting tasks, but can develop over time.
* It doesn't only occur when the User is performing other tasks, using the PC, etc.

I'm normalizing (?) some of my more extreme BOINC settings, in case they're at fault.
* From 90% of CPU time to 60% max.
* Suspend GPU when PC in use to not.
* Suspend when non-BOINC CPU usage above 60% to 33%.
* Switch between tasks every 300m to 60m.
* Tasks to checkpoint every 120s to 60s.

Given that BOINC works by default on FIFO sorting by deadline may well give you some strange drop-outs of tasks. Several things could be happening to cause this, first a "new" task get inserted into your list that moves a task within the list, so causing it to loose its place marker; a task is completed then replaced in the list with another one of similar deadline or display name.

A word of warning - trying, as you are, to micro manage the sequence that BOINC processes tasks can be counter productive, it is far better to let it run free as it will do its very best to run all tasks before their deadlines are reached unless you have some really crazy cache settings. Many have found when running multiple projects the best solution is to have a small cache (one or two days) with a very small fraction of a day additional cache.

One thing that has caused many confusion is the "use max CPU time" - this is uses a very short time-slice to achieve the required percent operation, and so puts a lot of stress on the CPU and all the associated chips as every time you reach the end of a time slice data is sent back to memory, and the CPU becomes unloaded thus suffering thermal stress - it is far better to run at 100% then use a CPU speed throttling program like TThrottle which regulates the clock speed and keeps the thermal load constant.
If you are worried about the impact of check-pointing then it is best to increase the time not decrease it - the time is the interval between the application storing snapshots to disk, and obviously the shorter the interval the more snapshots are taken. Remember that a snapshot is taken automatically when BOINC is shutdown or suspended.
Task switching - this interval really depends on the average duration of each task type being run, somewhere in the region og 1-3 hours is probably O for most, but some get really shirty if you swap too often :-(

One thing that has caused many confusion is the "use max CPU time" - this is uses a very short time-slice to achieve the required percent operation, and so puts a lot of stress on the CPU and all the associated chips as every time you reach the end of a time slice data is sent back to memory, and the CPU becomes unloaded thus suffering thermal stress - it is far better to run at 100% then use a CPU speed throttling program like TThrottle which regulates the clock speed and keeps the thermal load constant.
If you are worried about the impact of check-pointing then it is best to increase the time not decrease it - the time is the interval between the application storing snapshots to disk, and obviously the shorter the interval the more snapshots are taken. Remember that a snapshot is taken automatically when BOINC is shutdown or suspended.
Task switching - this interval really depends on the average duration of each task type being run, somewhere in the region og 1-3 hours is probably O for most, but some get really shirty if you swap too often :-(

But, using throttle will surely potentially affect whatever you are using the computer for apart from BOINC? Personally I think a much better solution is to restrict the number of cores in use if at all worried about heat issues.

As I rarely have more than one task queued per core and tend never to run tasks that are finished in less than a few days all from CPDN except when they don't have any, I suspect it is not surprising that I haven't seen this problem. If I ever get a machine that can crunch on GPU things might then change.

A possibility;

When sorted by deadline there will be a lot of duplicate entries (all WUs downloaded together will have the same deadline), does BOINC use a secondary sort criterion such as estimated time remaining?

My display is generally sorted by etr within status (sort by etr then sort by status and it will retain etr as a secondary key) and quite often the sequence of items in the list changes as one WU overtakes another.

This could also explain why it tends to happen after BOINC has been running for a fair while.

Thank you for replies, but please read my posts first. This does NOT have to do with sorting by deadline, as I've explained. The following test proves that, also.

In my test last night, I:
1. Unplugged my wireless mouse.
2. Rebooted.
3. Closed non-BOINC software: CCleaner, .
4. Opened BOINC manager.
5. Set Asteroids@home to "Won't get new tasks."
6. Changed the status of 10 Asteroids tasks to Suspended.
7. Used my keyboard to select the 10 suspended Asteroids tasks.
8. Left my computer alone for 11 hours.
9. Found the following:


This absolves my wireless mouse and CCleaner and Chrome. It also shows that it doesn't have to do with new tasks downloading with deadlines "in the middle" of my selected tasks, and that BOINC is selecting its own tasks for some reason, just as it deselects some (actually, most) of those that I'd selected.

Your screenshot shows that you still have tasks sorted by (ascending) deadline - so it may still be implicated, even if not directly by 'new task insertion'.

For my 3rd test, I'll choose some "Ready to start" tasks that I don't expect to run, since they were among the most recent to download, with the latest deadlines, with an entire page of prior tasks. To prevent new tasks from downloading "in the middle", I've turned all tasks to "Won't get new tasks":


The User-selected tasks are Rosetta@home tasks:


I'll add the results later, after I close all non-BOINC programs (Chrome and Paint 3D), sleep and return to check on BOINC.

How so, Richard? No new tasks are being inserted. No tasks in my list of 10 are running and dropping out.

I fail to see how sorting by Deadline has anything to do with it.


But if y'all are convinced that sorting by Deadline is at fault, what should I sort by? How do I un-sort?

I've seen the same behaviour when tagging a few tasks some of and the underlying list has changed contents, mostly when looking at the transfers page, where things can happen quite rapidly.
My thoughts are that each item in the list has a display position number (probably its location in the array of items), when an item is removed (by completing that task), or a new item is added (downloading a new task) there is some shuffling within the list, some tasks keep their old position number, others don't, and thus some "new" tasks get highlighted while others loose their highlighting. If this is what is happening then it is down to the way that the displayed lists are enumerated and displayed - and from memory that is a very ugly bit of code to walk through (even by BOINC standards).
One thing to remember is that, in most situations, highlighting (tagging) is only meant to be a short-term action on a dynamic list like the BOINC tasks or transfers displays.

I said it was a wild thought in my first reply - I was clutching at straws, because I've never, ever, seen this.

I've now set an experiment running, in a 'New BOINC Manager window...' - because experience tells me that changes made in a secondary window aren't permanent.

Which brings me on to one of my pet peeves. The only way I've found to remove a sort, once applied, is to close BOINC Manager entirely (you can leave the client running), and edit the registry.

In regedit, navigate to [HKEY_CURRENT_USER\Software\Space Sciences Laboratory, U.C. Berkeley\BOINC Manager\Tasks], and set

"SortColumn"=dword:ffffffff

That's equivalent to column -1 - used as a null column value.

Yikes! The registry?

I wondered where BOINC was storing settings. Looks like it has some XML files in subdirectories of c:\ProgramData\BOINC, but none of them contain the word "sort".

You could always switch to Linux - then the settings are stored in hidden files.

Someone took over my BOINC for awhile. I didn't know that was possible, remotely.

It's back in my possession, and the issue remains. It affects also "Ready to start" tasks, when sorted by Deadline. I'll test sorting by Project, secondary sort Application next.

And the odd deselecting/selecting behavior occurs when tasks are sorted by Project primarily after Application secondarily. So it's not just a Deadlines thing.

I clicked on every other field, then Application, then Project. Some of the tasks selected did run, but it was clear it still happened.