Upgrading to version 17.1.1 causes the multi column combo box to be unresponsive and hang the browser page.

[Noah]

                  <kendo-multicolumncombobox [fillMode]="'flat'" [readonly]="!canEdit() || invoice().isPosted" #vendorList [data]="vendors()"
                    [filterable]="true" (filterChange)="handleFilter($event)" textField="display" valueField="id"
                    formControlName="vendor" [valuePrimitive]="true" (valueChange)="onVendorChange($event)" [popupSettings]="{width: '75em'}">

 

that is how it is being used.  all the values being accessed with () are signals and not methods that should get endlessly called (except for the filter and value change handlers)  But in 17.1.1 if you try to expand the dropdown or change the filter it grinds the whole page to a halt and the entire browser page becomes unresponsive.

Reverting to 17.1.0 fixes the issue.

[Zornitsa]

Hi Noah,

Based on the provided information and code snippet, I tried reproducing the described scenario of the MultiColumnComboBox when using the latest v17.1.1 of the DropDowns package in the following StackBlitz example:

• https://stackblitz.com/edit/angular-phmx39js

In the above example, the MultiColumnComboBox has filtering configured and uses signals for its data binding and the readonly property's definition. As it can be observed, the demo uses v17.1.1 of the DropDowns package and seems to behave as expected when opening the component and filtering its data. 

With the above being said, can you please check out the linked StackBlitz example and compare it with the implementation on your side to determine any differences that might possibly cause the experienced issue on your side? In addition, it would be great if you could modify the example in a way that the issue is reproduced and send it back to me for further observation.

In that way, I will be able to actually observe the problematic behavior on my side and thus provide more valuable assistance on the matter, since currently, it is hard for me to figure out an exact reason for the experienced issue. 

Please observe the provided information and let me know how it goes.

Regards,
Zornitsa
Progress Telerik

[Noah]

I guess it had to do with the size of the list of items in the dropdown. It was getting 500 items. I don't know why the performance degrades so much in version 17.1.1 vs 17.1.0, but adding virtual settings makes it run ok.

You can see the issue by just running your default virtualization example in stackblitz.  Notice how much slower the list of 1000 items opens in version 17.1.1 vs 17.1.0 with virtualization off.   It goes from a fraction of a second to about 3 seconds to open between the two versions.  I don't know what else my setup was doing to exacerbate the issue, but it would hang the browser completely for some users and took about 10 seconds to open the list for me vs a fraction of a second with version 17.1.0.

Also, another issue you can see with the popup settings and virtual. If you use a string css value of say "50em" for the popup settings width AND you use virtual, the column widths of the data do not match the headers.  Using 50em WITHOUT virtual and the table formats properly.  Using 700px instead of an em or rem value works although it's not pixel perfect.

[Zornitsa]

Hi Noah,

Thank you for the additional clarifications provided.

Given the shared explanation, I tested the performance of the MultiColumnComboBox in both v17.1.0 and v17.1.1, which is the version you mentioned when the performance has decreased. On that note, I was indeed able to observe the evident decrease in performance of the MultiColumnComboBox in v17.1.1 with both virtualization enabled and without, and after further consulting the matter with a developer on our team, the behavior turned out to be a regression bug on our side. 

With the above being said, I logged the following bug report in our public GitHub repository that addresses this issue:

• https://github.com/telerik/kendo-angular/issues/4494 

Feel free to follow the above issue in order to stay notified in a timely manner with any updates on the future fix implementation for the MultiColumnComboBox bug.

As a small token of gratitude for reporting this behavior and helping us improve the quality of our product, I have updated the Telerik points of your account.

Regarding the additional reported issue about the misalignment of the MultiColumnComboBox's columns when setting the popupSettings width, I want to assure you that we will further look into this matter to identify whether the behavior is expected or not. 

In this line of thought, we apologize for any inconvenience that the reported MultiColumnComboBox performance bug might have caused on your side.

Regards,
Zornitsa
Progress Telerik