* Changed the handleSessionExpired logic to return a 404 instead of a 410. Also added the no-cache parameter to the reply.
See https://github.com/vaadin/framework/issues/4417 for discussion.

* Code format

* Merge branch 'master' into code-format

- Replace the GridDisabledTest screenshot usage
- Replace the screenshot tests in BasicCrudGridEditorRowTest
- Replace the screenshot tests in ComboboxVaadinIcons
- Replace the screenshot tests in ValoThemeUITest::accordions
- Added screenshotcomparetolerance to some screenshot test to make tests stable

Spring add-on needs to use these added methods in order to fix #10922

issue in #11343 and #11385 is not reproducible on top this patch
Three different bugs are involved in this fix:
we bring the old fix(#11094) back and fixed the other related issues:
1) allow adding the same new item after dataProvider got reset, This is cause by the client side parameter `LastNewItemString`, it saves the value added before resetting. 
2) clear the pending newItem eagerly, so that the same value will not be added again.

* Update to 8.9-SNAPSHOT

* update in bom module

* Create StringToUuidConverter.java

Implements the `Converter` interface, to support converting back-and-forth between `String` and `UUID` (a type built into Java 5 and later).

See Issue # 11,051.
https://github.com/vaadin/framework/issues/11051

* Formatting cleanup, remove sinces

* Clicking on slider makes handler move

Fixes #1496

* Introducing control over clicking behaviour

- User will have to enable process of the click event on handle calling `slider.setEnableClickHandler(true);`
- Clean-up the handler logic in VSlider.java
- Renaming the property to `updateValueOnClick`
- Added JavaDocs
- Fixing tests

Newer Chrome versions do not work with random number hack to prevent auto completion, but it finally supports autocomplete=off.

Adapted from https://github.com/vaadin/framework/pull/11472

Fixes #11437

* Fixing autocompletion issue with ComboBox on newer Chrome versions

Newer Chrome versions do not work with random number hack to prevent auto completion, but it finally supports autocomplete=off.

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Merge branch 'master' into fix11437

* Added note about Java 8 vendors

* Update release-notes.html

* Add delay to the unstable test

* Fixes 11517. Use ENTER and SPACE keys as shortcuts for header buttons

* Merge branch 'master' into fix-11517

* Increase sleep time for test failing in validation

* Merge branch 'master' into fix-11517

* Update screenshots after chrome updates

* Update screenshots after chrome updates

* Reset selection on DataProvider change in RadioButtonGroup

Fixes #11454

Other components needing the same fix are ListSelect,NativeSelect,Combobox (The ones implementing HasDataProvider and extending AbstractSingleSelect. Grid is not affected as it extends AbstractListing and hadles selection differently)

* Added test case

Verify that ValueChangeListener is actually fired after value is reset setting new DataProvider

Fixes 11528

Verify that correct mode(HTML/TEXT) of caption is set for the  Panel
Fixes #11521

Fixes #11489

If you use multiple UIs, the use of SLF4J would depend on the UI initialization order which could be pretty random. If you have multiple servlets, it's even better to init SLF4J in ServletContextListener.

Fixes #11502

Documents the possibility to use vaadin:// and theme:// in JavaScript and StyleSheet annotations.

Fixes #8675

Add DataChangeHandler removal in v7 Grid just as in v8 Grid.
Adding tests to the fix to verify, that NPE is not thrown.

Add check for the V8 TextField used in Table in compatibility mode. This makes clicking cell with the TextField select the row, preserving behaviour from V7.
Through, as it's noted also before, this is an improved workaround, not a proper solution to address the issue.

Fixes #11474

Removed link to and recommendation  for SQLContainer

Make improve of caching for hierarchical data optional

Fixes #11477

If BrowserWindowOpener is used with constructor using Class<? extends UI> as parameter, it will have UI provider with generated url. This will not match UI beans in contextual storage and hence newly created UI will not be managed bean. Due this, injection to new UI instance will not happen. If you are using CDI , BrowserWindowOpener(String) constructor needs to be used.

Fix example of using grid.setStyleGenerator in one line

Explicitly reset the value in case if it was cleared.
Ignore the case for selecting a suggestion.

Fixes vaadin/testbench#1122

* Add Test file

* Remove redundant check for for Firefox

It seems that in older versions of Firefox (at least, older than 45) the KeyPress event should be used instead of KeyDownHandler. At some point (works already on 58 version, the current one is 65) the issue was resolved and starting from Firefox 65 this hook prevents from navigating in the pop-up via keyboard.
Simply removing additional logic makes navigating in both DateField and InlineDateField possible

Fixes #11465

Checking that no prior Combobox behavior is broken

* Cleaning-up the code

Adding UI test

* Adding TestBench test

* Fixing NPE when ItemCaptionGenerator returns null

Adding similar logic in setDataProvider(...) as used elsewhere in ComboBox.java (e.g. generateData(..) see line 314)

fixes issue #11434

* add accessor methods for CUSTOM_SERIALIZERS in JsonCodec

* javadoc

* removed removeCustomSerializer method, renamed putCustomSerializer to addCustomSerializer, added sanity checks and JavaDocs

* refactored addCustomJsonSerializer to set, added test UI

* move enums to be parsed after custom serializers

* move adding custom serializer to static block

* throw an exception if multiple serializers are registered for class

* updated javadocs

* changed CustomJSONSerializerTest to a SingleBrowserTest

* moved CustomJSONSerializerTest to server/ and it's now not a browser test

* removed CustomJSONSerializerTest

This fix was already applied to com.vaadin.client.ui.VCheckBox but the committer forget to apply the same fix to the com.vaadin.v7.client.ui.VCheckBox. Some people are still temporarely using the checkbox from the compatibility package.

Fixes #11451

* Fix an NPE caused by the previous fix to Grid's frozen columns (#10653)

If the user managed to get two frozen column count changes into a single server round-trip before the component had been attached, the previous fix  #11346 lead to a null pointer exception since there was no diff state available.

This fix adds a null check before removing the frozen column count value from the diff state so that this will not happen.

Closes #10653