Approved
Last Updated: 05 Sep 2019 10:39 by ADMIN
Dirk
Created on: 23 Aug 2019 08:14
Category: ComboBox
Type: Bug Report
0
Infrequent NullReference in grouped combobox while filtering

Hi,

we found a hard to reproduce bug in the combobox control. It appears infrequently while typing in the combobox input, if the combobox has grouping and the fixed header enabled. It does not seem to have functional implications to the control but it produces a javascript error.

Stacktrace:


_firstVisibleItem: function () {
    for (var t = this.element[0], n = this.content[0], i = n.scrollTop, r = e(t.children[0]).height(), o = Math.floor(i / r) || 0, a = t.children[o] || t.lastChild, s = a.offsetTop < i; a; ) if (s) {
      if (a.offsetTop + r > i || !a.nextSibling) break;
      a = a.nextSibling
    } else {
      if (a.offsetTop <= i || !a.previousSibling) break;
      a = a.previousSibling
    }
    return this._view[e(a).data('offset-index')]
  }

It seems to be a timing problem where the list is already loading again while the scroll from the item selection is not finished.

3 comments
Missing User
Posted on: 05 Sep 2019 10:39

Hi Dirk,

I have investigated further and indeed the described behavior is a bug, but I'm afraid currently we do not have a workaround for this issue.
I have reported this as a bug in the Kendo UI GitHub repository from where you could start tracking it:

Also, I have updated your Telerik Points as gratitude for reporting the issue.

Regards,
Aleksandar
Progress Telerik

Get quickly onboarded and successful with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.
Dirk
Posted on: 29 Aug 2019 13:56

Hi,

as mentioned, it is a bit tricky to reproduce. I built a dojo snippet to test it: https://dojo.telerik.com/EkoYaVar/2

Steps:

1. Open Dropdown

2. Put cursor into text input

3. Hold down the arrow down key and start scrolling

4. Somewhere down the list (fixed header must have to change), enter any other letter while scrolling down

-> Console shows error

Greetings,

Dirk.

Missing User
Posted on: 29 Aug 2019 13:39

Hi Dirk,

Thank you for reporting this issue. I tried reproducing the described behavior, but I did not manage to replicate the described.

Would you be able to provide a sample solution which isolates the described scenario? Also sharing the exact steps to reproduce the error would be helpful in resolving the issue. Please, also tell us if there is anything else specific for the environment where the reported problem is observed.

Looking forward to hearing from you.

Regards,
Aleksandar
Progress Telerik

Get quickly onboarded and successful with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.