ComboBox mouse wheel scrolling slow on Chrome

Hello,

I'm experiencing an annoying behaviour with ComboBoxes :

In Google Chrome (v 54), when scrolling with mouse wheel through a combobox with multiple pages, switching to the next/previous page takes a very long time (something like 3 seconds). 
I looked at Chrome's Developer Tools window, and I can see that the call to the server to fetch the next data is very fast, so the problem is not here, it looks like it's only the client that takes a long time to display the page.
When using the keyboard to scroll (typing filter text in the combobox, using the arrow keys, or using page down/page up keys), or when clicking the little arrows, loading the other pages is fast, so the problem is only when using the mouse scroll wheel.

I also tried with Internet Explorer 11, and there is no problem there.

Is this a known bug ? If not, any idea where I can look to find out what's happening during these long seconds ?

Thanks.

Hi,

here's a similar reported issue: https://dev.vaadin.com/ticket/14148

It's very light on details, though, so if you have time, it'd be helpful to have some more info or even a test project where the error shows.

-Olli

Hi,

Thanks for the reply.

For me, here is how to reproduce the problem :
- Create a maven vaadin-archetype-application project

mvn -B archetype:generate -DarchetypeGroupId=com.vaadin -DarchetypeArtifactId=vaadin-archetype-application -DarchetypeVersion=7.7.0 -DgroupId=com.foo -DartifactId=foobar -Dversion=1.0-SNASHOT

- Add this to MyUI.init :

ComboBox c = new ComboBox();
        for(int i = 0 ; i < 100 ; i++) {
            c.addItem("data " + i);
        }
        layout.addComponent(c);

- Launch the application on Tomcat 8 from Eclipse
- Run from Chrome and scroll the list.

Do you need other information ?

Thanks.

Thanks, that'll help; I've added your description to the ticket.
-Olli

Can you reproduce the problem, or is it related to my configuration ?

Yeah, it even happens if I run it on Jetty.

-Olli

Thanks for confirming.

Do you know if there is a way to fix that or a workaround ?

The only workaround I can think of is to not use a paginated ComboBox (set the pageLength to 0).

If you can make a fix in the Framework, you can submit a pull request in GitHub and it'll be included once it passes the review process and can be released (ie. it doesn't break anything else and meets the submission criteria). If you need to get it fixed for you by the dev team and can't wait for them to pick it up from the backlog, you can contact Support and request a Bug Fixing Priority.
 

Disabling paging is ok for me for now, thanks.

I'm not sure I have enough experience with Vaadin to fix this myself, but I'll keep that in mind.

Thank you for the support, Olli.

Happy to help, even a little. In case you ever want to take a look at the Vaadin Framework, building it yourself became a lot easier a while ago as it can now be done with Maven.

-Olli