Chrome Version: 64.0.3282.169
OS Version: 10176.73.0
UserAgentString: Mozilla/5.0 (X11; CrOS x86_64 10176.73.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.169 Safari/537.36
Device: Google Pixelbook & Pen

What steps will reproduce the problem?
1. On a convertable Chromebook, fold into Tablet Mode
2. Long-press on the shelf, to open the customisation context menu
3. Try to set shelf position to Left or Right

What is the expected result?
The customisation context menu's 'Shelf position ❯' submenu ought to allow the user to set their desired shelf postion to either Left or Right or Bottom, just like it does in Laptop Mode.

What happens instead of that?
From Chrome OS 64 to 66, in Tablet Mode (and also in Tent and Entertainment Modes, too), the customisation context menu's 'Shelf position ❯' submenu is now greyed out and inoperable; ie: the previously available user-determined FLEXIBILITY to choose Left or Right shelf position in Tablet & Tent & Entertainment Modes has been removed, to be replaced by a developer-dictated INFLEXIBILITY: shelf position Bottom has become mandatory, and impossible to change (save for the awkward temporary workaround detailed below).

What happened in previous versions?
In Chrome OS 62 and 63, in Tablet & Tent & Entertainment Modes, the customisation context menu's 'Shelf position ❯' submenu correctly allowed the user to set their desired shelf postion to either Left or Right or Bottom, just like it does in Laptop Mode.

How Many Related Issue Reports Are There?
These are the reports I've discovered so far; there may be others which I've not discovered yet.
● 'Shelf in tablet is not always on bottom', 06 Dec 2017
» https://bugs.chromium.org/p/chromium/issues/detail?id=792353
● 'Chrome OS shelf appears incorrectly when going into tablet mode', 11 Jan 2018
» https://bugs.chromium.org/p/chromium/issues/detail?id=800999
● 'unable to change the shelf position in tablet mode', 31 Jan 2018
» https://bugs.chromium.org/p/chromium/issues/detail?id=807701
● 'Shelf position not adhering to user-set preference when switching to tablet mode', 18 Feb 2018
» https://bugs.chromium.org/p/chromium/issues/detail?id=813430

● 'Autohide shelf and Shelf position options becomes available in Tablet mode', 23 Feb 2018
» https://bugs.chromium.org/p/chromium/issues/detail?id=814976
● 'Why Can I No Longer Choose Shelf Position in Tablet Mode?', 01 Mar 2018
» https://productforums.google.com/forum/#!topic/pixelbook/8XXiGakpREA

Is There A Workaround?
Here is an awkward temporary workaround (for Chrome OS 64 & 65) for retaining my favoured RHS shelf position in Tablet Mode:
1. Set orientation to 'Auto rotate', unfold to Laptop Mode, and close all windows in order to view the desktop wallpaper image
2. Long-press on the wallpaper to open the fully fuctional Laptop Mode customisation context menu – ie: where the 'Shelf position ❯' submenu still works – and set 'Bottom'
3. Long-press on the wallpaper again, to re-open the fully fuctional Laptop Mode customisation context menu, then refold into Tablet Mode
— the context menu stays on screen, and the 'Shelf position ❯' submenu still works
4. Use the 'Shelf position ❯' submenu to set shelf position to 'Right'
— shelf position moves to 'Right' in Tablet Mode

Why Has Increasing Chromebook Hardware FLEXIBILITY Been Scuppered By Chrome OS Software INFLEXIBILITY?
The current positive and progressive trend towards increasing hardware FLEXBILITY in Chromebook form factor design – now: 360°-hinged 4-in-1 convertables; soon: tablet/laptop detatchables – is undoubtedly a Good Thing. So this apparent countervailing trend towards increasing software user-interface INFLEXBILITY in Chromebooks – ie: REMOVING the Left and Right shelf position options in Tablet, Tent, and Entertainment Modes – strikes me as perverse, restrictive, and illogical.

One of the reasons why computer users favour community-developed FOSS over private and proprietary software (from, eg: Micro$oft, Apple) is the  opportunity to positively influence the way our computers work, rather than just having to resentfully put up with whatever developer-dictated "improvements" get foisted upon us by paternalistic, developer-knows-best, for-profit corporations. So I have:
(1) posted feedback via 'Settings > About Chrome OS > Report an issue' (aka the alt+shift+i mechanism);
(2) posted a 'Why Can I No Longer Choose Shelf Position in Tablet Mode?' thread discussion starter in Google Product Forums (linked above); and
(3) posted this comprehensive Issue Report via the Chromium project bug report mechanism.

If bug reports are not the most appropriate method for positively influencing Chrome OS development, please post a comment below containing a pointer to where this issue is being discussed between end users and Chrome OS developers.

Why Has The Chromebook User Experience Been Deliberately Degraded?
As a right-handed Pixelbook & Pen user, who uses landscape Tablet Mode 98.5% of the time, it's simply most ergonomically efficient to position the shelf on the right hand side (RHS) of my Tablet Mode screen. So from 23 Nov 2017 (delivery day, with factory default Chrome OS 62), through to 25 Feb 2018 (including an update to Chrome OS 63 on 12 Jan 2018), my Tablet Mode shelf position was on the RHS of my screen. But on 26 Feb 2018, I updated to Chrome OS 64 – and now I'm being officially FORCED to have my Tablet Mode shelf position at the BOTTOM of my screen.

Online research reveals that, unsurprisingly, I'm not alone in strongly objecting to this deliberate, developer-dictated, degradation of the Chromebook user experience, as indicated by the comments below.

● "I hate this change! I like the shelf on the right so I can just swipe it in with my right hand naturally and select.  On the bottom of the screen it is finicky to work with, and makes the screen too short as well.  Also I want the shelf hidden, I often want full screen apps in tablet mode.  Why would you override my preference?  I set it to be on the right and auto-hide, please don't fuss with my preference."
~ wpwoo...@gmail.com, 12 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c4

● "This change is extremely annoying! Why would my preference (to keep the shelf on the left side of the screen and to have it auto-hide) be overridden when moving into tablet mode? I honestly thought this was a bug and spent more than an hour sending feedback, trying to track down fixes, etc."
~ d51...@gmail.com, 13 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c9

● "I did have an issue with the new behavior, running the Android app Squid for drawing, where my palm was resting on the shelf at the bottom of the screen (instead of on the right where it used to be), and caused the settings tray to be displayed while I was trying to draw."
~ wpwoo...@gmail.com, 14 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=800999#c4

● "The change is still ridiculous. Let us make our own decisions and set our own settings. You're fast on your way to becoming Apple making all choices for us and justifying it with facts and figures that no one else has any knowledge of."
~ d51...@gmail.com, 13 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c14

● "I'll add my voice to those who dislike the change. I too have my shelf on the right and hidden and would like the shelf behavior preserved while in tablet mode."
~ thomas.c...@gmail.com, 15 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c15

● "I changed my shelf settings to left side specifically for tablet mode.
If the shelf is at the bottom in tablet mode, my wrist and sleeve would cause false touches that activate the shelf when I use notetaking apps (such as Squid) on Samsung Chromebook Plus. Even autohide does not help: moving my hand up (happens regularly when writing with stylus) causes a false "swipe up from the bottom" touch and unintentional shelf reveal, which is often then activated accidentally. Having the screen switch to expose mode without warning is a pain.
The only way I have found that reliably prevents the false shelf (and shelf widget) activation is to move the shelf to the left (I am right-handed). Forcing this shelf to the bottom will significantly degrade stylus experience, which I understand is becoming an important use case for 2-in-1 Chromebooks.
Please think of the poor stylus users - especially since those of us are typically Chrome OS loyalists who pony up for premium (2-in-1 with stylus) devices."
~ chk...@gmail.com, 15 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c16

● "I have a similar complaint to #16. When I'm taking notes in Squid on the PixelBook, I inadvertently hit the shelf and open up random apps that I had no intention of opening. It's very annoying."
~ seldnp...@gmail.com, 15 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c17

● "The option to change shelf position was working fine for me for the last year of use, right side with auto hide. Then some nerd with a bunch of numbers decides "I" do not need a feature "I" paid for. Change it back, allow me to choose the setting I want, and stop screwing with "MY" property."
~ sold23rd...@gmail.com, 17 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=792353#c20

● "While this change to Chrome OS (not just Pixelbooks) is working as intended, it's also wildly unpopular. Please add your feedback via alt-shift-i."
~ Joe Ellett, 02 Mar 2018, https://productforums.google.com/d/msg/pixelbook/8XXiGakpREA/Hn4-Xcr8AwAJ

● "Some of us have already strongly objected to the change and encourage everyone else to also express their opinion.
This impacts all convertible devices, not just Pixelbooks.
Use alt+shift+i to report it."
~ Jim Dantin, 02 Mar 2018, https://productforums.google.com/d/msg/pixelbook/8XXiGakpREA/ONMPAG0OBAAJ

● "Can someone explain *why* the shelf should be on the bottom in tablet mode? Why should it not be a configurable option *regardless* of device orientation?
I often use my device in landscape tablet mode and it's incredibly annoying to have the shelf on the bottom vs. the left where I would prefer."
~ cko...@gmail.com, 03 Mar 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=807701#c7

● "How can this be working as intended when it borks stylus usage? Please come up with a solution to that problem.
When writing with a stylus, palm touches on the shelf often activate other apps, the notification area, or the Overview screen, making it very hard to write comfortably. This is one of my primary uses of the PixelBook, and it has now become a frustrating painpoint."
~ seldnp...@gmail.com, 03 Mar 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=813430#c5

Is There A Constructive Way Forward?
In seeking a valid technical justification for deliberately degrading the Chromebook user experience, the only evidence I've discovered is this comment:

● "Apps rely on only resizing vertical space, which can cause apps to break if we move to shelf on the side for tablets."
~ omrilio@chromium.org, 12 Jan 2018, https://bugs.chromium.org/p/chromium/issues/detail?id=800999#c3

I'm sorry, but this seems to me to be of the order "This issue looks way too difficult to figure out, so let's just take the easy option, and restrict our end users' freedom of choice of instead."

I trust that we can agree that Chrome OS provides the all-encompassing software environment, including the user interface, within which apps provide their useful functionality. So attempting to assign responsibility for a novel user-interface freedom restriction on to apps smacks very much of a 'tail wagging the dog' category error excuse for lacklustre and laxidasical OS development (IMHO).

For a number of valid ergonomic and usablility reasons, many end users clearly place a high value on the flexibility previously afforded by Tablet Mode shelf positions Left and Right, so I would politely request that the Chrome OS development team:
● make a conscious collective decision to revisit this contentious issue;
● acknowledge the "wildly unpopular", "frustrating painpoint", and "incredibly annoying" negative nature of the poular end user reaction to this novel, developer-dictated, user-interface freedom restriction;
● figure out a way of reliably resizing apps horizontally, to thereby enable Tablet & Tent & Entertainment Modes to again support Left and Right shelf positions; and
● re-enable full 'Shelf position ❯' submenu functionality for Tablet & Tent & Entertainment Modes as soon as possible.

Thanks in advance for your time and attention in rectifying this issue.