Sheet: loosing data when working fast, possible bug?

Describe the bug

Some of our users work fast in a sheet, all changes look ok, possitive growl feedback, but after F5 a lot of changes are reverted.

client side I do <p:ajax event="change" update="@none" listener="#{perceelSheetController.cellChangeEvent}"

serverside I have a sessionscoped bean, that stores updates, handles errors and applies client update logic.

Serverside I tried synchronizing, locking. Clientside I tried eliminating other events than change, updating the whole sheet in onchange seems to help but leads to a hard to fix scrolling problem.

I cannot yet exactly pinpoint the problem, not even after extensice debugging client and server, but it looks like a client side problem where the browser sends data before everything that should be completed is completed.

Do some other users of sheet experience problems like this? Could I overlook something crucial?

Reproducer

Sorry, no reproducer yet

PrimeFaces Extensions version

11.0.2

JSF implementation

Mojarra

JSF version

2.3

Affected browsers?

firefox

Steps to reproduce the behavior

No response

Expected behavior

updates applied and saved

Sample XHTML

            <pe:sheet id="sheet" widgetVar="sheetWidget" value="#{perceelSheetController.percelen}" var="row" rowStyleClass="#{row.id == null ? 'nieuw' : ''}"
                      rowKey="#{perceelSheetController.getRowKey(row.id)}" showRowHeaders="true" 
                      resizableCols="true" resizableRows="true" filteredValue="#{perceelSheetController.filtering.filtered}"
                      readOnly="#{not accessController.mayEdit()}">

                <p:ajax event="change" update="@none" listener="#{perceelSheetController.cellChangeEvent}" 
                        onerror="window.setTimeout(function() {focusFirstSheetError('sheetWidget');}, 200);"/>
                <p:ajax event="cellSelect" update="@none" listener="#{perceelSheetController.cellSelectEvent}" disabled="#{perceelSheetController.isChangeErrors()}"/>

Sample Bean

    public void cellChangeEvent(final SheetEvent event) {
.
# I show only the last bit of what this function does because calling update ajax().update( might cause the problem?
.
        JsfUtil.addSuccessMessage("Saved " + percs.stream().map(p -> perceelConverter.getAsString(null, null, p)).collect(Collectors.joining()));
        List<String> pfupdates = new ArrayList<>(3);
        if (gemStatusChange) pfupdates.add("menuform");            
        if (nieuwPerceel) {
            PrimeFaces.current().executeScript("sc();");
        } else {
            pfupdates.add("buttons");            
        }
        if (!pfupdates.isEmpty()) PrimeFaces.current().ajax().update(pfupdates);
    }

[eduarddrenth]

Yes, therefore cellselect event is async=true, change event is async=false, change method is synchronized, jpa and optimistic locking garantee data integrity, this probably fixes the issue (awaiting testers)

[eduarddrenth]

This issue I solved like this:

• in xhtml make cellSelect call asynchronous async=“true”-

<p:ajax event="change" update="@none" listener="#{perceelSheetController.cellChangeEvent}" 
                        onerror="window.setTimeout(function() {focusFirstSheetError('sheetWidget');}, 200);"/>
<p:ajax event="cellSelect" async="true" update="@none" listener="#{perceelSheetController.cellSelectEvent}"/>

• in Java bean make change method synchronized:

    public synchronized void cellChangeEvent(final SheetEvent event) {