Another thought: we could also try refreshing every 125msec for 5
seconds after the first change is detected. It's a bit yuck perf-wise
but would probably be pretty transparent to the user.

In testing, this looks good. It means the changes appear as soon as
ready, without substantial delays or performance issues. Polling this
makes me feel a bit dirty, but I'll just take a shower and be okay.

As Keyman now monitors the Windows keyboard list from Control Panel, it
is no longer sufficient to refresh the toolbar only when a Keyman
keyboard is updated, as at that point Windows has not refreshed its own
language list in the registry. Instead, we need to monitor changes to
the relevant registry key and then refresh when those changes are
'complete'.

There is a problem: there does not appear to be a good way to monitor
for changes to Windows language settings. WM_SETTINGCHANGE is sent when
a language is added by the user in Settings, but the actual change
happens asynchronously, and we are not notified when the changes are
complete.

We also do not get notifications when languages are added via APIs.

Given the async nature of the language profile changes, this leads to
race conditions when we try to refresh the OSK toolbar. My preferred
solution currently is to monitor the relevant key in a separate thread,
and wait 1 second post-changes to actually do the refresh.

Fixes #4006.

This fixes the list error exception which was masking the actual cause
of #4006, which is already fixed by #4164.

Related issue #4119 is also fixed by #4164.

When a keyboard is installed, Keyman will now only refresh its internal
state on a given thread when that thread receives focus and/or input,
rather than immediately. This will dramatically reduce the chatter
caused by Keyman Engine when a keyboard is installed or settings are
changed.

Fixes #4011.
Fixes #4039.
Fixes #4121.

This change completes the immediate-change model for Keyman
Configuration, by refactoring the refresh of settings out of the render
phase and more appropriately splitting applying and refreshing. It adds
a new message flag for wm_keyman_refresh, KR_SETTINGS_CHANGED, which
uses a random token approach broadcast to all applications on the
desktop to ensure that the refresh is received and multiple
notifications for the same event can be appropriately coalesced.

Most of the files touched are stripping out the refresh flags from the
render phase.

There is one small bug resolved at the same time with the options
properties, which were not reset to default if they had been deleted
from the registry prior to a refresh (see utilkeymanoption.pas).

Fixes #3749.
Fixes #3759.

Adds a warning dialog when user attempts to add a transient language to
a keyboard but the maximum number of transient languages is already
installed.

If this issue arises when a user is installing a keyboard for the first
time, Keyman instead installs the keyboard for the user's default
language. This may be a little confusing, but the error condition is
difficult to explain and non-technical users will probably be stuck
and need to install under their default language in any case. Happy to
receive any pushback on this decision.

fix(windows): Text editor font bugs

fix(windows): help window centred on load

fix(windows): Canonicalize BCP 47 tag on keyboard download

fix(windows): remove obsolete option 'Switch to OSK/Help'

fix(windows): menu scroll positions need reset at popup

fix(windows): glitch in keyboard menu

chore(windows): remove obsolete importkeyboard app

auto: increment beta version to 14.0.211

fix(windows): beta uses wrong server

Fixes #4008.

Fixes issue of font helper popping out separately and secondary crash,
as well as the font helper not actually working because the font data
was never passed in.

In the future, we could improve this by moving the font enumeration into
the back end web server thread but that's a bigger refactor and not
appropriate for beta.

Fixes #4004.

Centres the help window when it first appears.

There is still a small resizing event but that will be handled with a
separate PR for #3765.

Fixes #4111.

The keyboard tag passed in from search would  often be missing a region
tag which is required on Windows.

Fixes #4113.

The option "Switch to On Screen Keyboard/Help automatically when a
keyboard is selected" is obsolete and we should remove it from the UI.

Note that this does not remove the API surface, just hides the option
from view, as there may be apps relying on the API value.

Not touching help just now as that will be addressed in a help update
in the future.

Fixes #4012.

If the menu previously was scrollable, then it would potentially show
items at the wrong offset because the offsets were not reset when the
menu popup was called if no scroll was needed.

Fixes #4112.

Glitch in keyboard menu from scrollable buttons being drawn at top-left.

Functionality has been ported to kmconvert.

Fixes #4042.

auto: increment beta version to 14.0.210

chore: fix trigger for beta branches

auto: increment beta version to 14.0.209

chore: re-trigger beta

auto: increment beta version to 14.0.208