Google has a fairly significant change in the works pertaining to how Chrome OS users activate a right-click that could result in some initial confusion, based on changes spotted by 9to5Google in the Chromium Gerrit and Chromium Bug Tracker.
Both point to a decision by Google to change the mouse behavior in Chrome OS to include a keyboard shortcut that uses the 'search' key instead of the 'alt' key, in combination with a click, to kick off a 'right-click' event. Comments in the Chromium Bug Tracker — stemming back as far as 2013 — provide a bit more detail in that they specifically point to a discrepancy in how the system uses the 'alt' key to instantiate a right-click in some web apps.
Changes to the Chromium Gerrit are more recent, highlighting that changes are actually already in the works behind a 'flag' setting in the browser. Referred to in the hidden flags menu as a toggle to "Enable Right-Click Remapping Transition," the setting allows the change to be tested before it's rolled out to end user and was added as recently as May 21.
What could go wrong?
As noted by the source, the decision to change things over has been tried before using exactly the same alteration — switching to a 'search+click' from an 'alt+click'. That was way back in 2015 and the change ultimately fell through because of various bugs associated with that right-click method. It's not unlikely bugs and unwanted behavior will appear with the new push to change things too.
Leaving alone any deeper code-based bugs that could arise, Google has made a lot of headway in using the search key for other things such as activating the search bar in the primary UI. Many users both in and out of the Chrome OS developer community likely already use the key to rapidly access that search bar.
In fact, at least one comment in the Chromium Bug Tracker decrying the use of the 'alt' key says that the search key causes problems as well because it causes the search bar to pop up. Written by developers for the Figma web app in late 2018, the comment notes that using 'search' simply isn't a viable option for that reason.
Arguably, a long-press on that button could potentially serve a better function, being used to access Google Assistant without the need for a new key on the keyboard.
Alt-Click also doesn't seem to have any noteworthy issues in many web apps, including the full run of GSuite apps. Instead of resulting in the web browser context menu, right-clicking in those apps brings native-like functionality in the form of an app-aware context menu.
Changing that behavior to a different combination of keys will probably be disruptive for a sizeable percentage of users who have already been using Chrome OS for quite some time.
Google will offset issues with the change-over via a warning
According to the bug tracking reports for the apparent issue, Google hopes to solve the problem at some point between the release of Chrome 75 and Chrome 77. So there's still plenty of time for end users to get used to the idea of right-clicking with a press of the 'search' key if Google follows through with the change. Conversely, that provides time for feedback to be gathered too.
It also appears that during that transition period Google will be allowing users to utilize either the 'alt' or 'search' key. A click to instigate a right-click action using the 'alt' key will cause a pop-up notification set to appear at an interval and letting users know they need to change over to a 'search' click — effectively warning of the impending change.