SplitButton: Prevent querySelector from running on undefined

[rosslavery]

Check that the ul exists before possibly running querySelector on undefined.

Prevents the following error:

ERROR TypeError: Cannot read property 'querySelector' of undefined
    at DropDownButton.push../node_modules/@syncfusion/ej2-splitbuttons/src/drop-down-button/drop-down-button.js.DropDownButton.removeCustomSelection (drop-down-button.js:304)
    at Observer.<anonymous> (drop-down-button.js:411)
    at Observer.push../node_modules/@syncfusion/ej2-base/src/observer.js.Observer.notify (observer.js:84)
    at DropDownButton.push../node_modules/@syncfusion/ej2-base/src/base.js.Base.trigger (base.js:152)
    at DropDownButton.push../node_modules/@syncfusion/ej2-splitbuttons/src/drop-down-button/drop-down-button.js.DropDownButton.closePopup (drop-down-button.js:408)
    at DropDownButton.push../node_modules/@syncfusion/ej2-splitbuttons/src/drop-down-button/drop-down-button.js.DropDownButton.mousedownHandler (drop-down-button.js:351)
    at HTMLDocument.__trace__ (bugsnag.js:2211)
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:421)
    at Object.onInvokeTask (core.js:17289)
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:420)

[sangeethapriyaM]

Hi @rosslavery ,

Greetings from Syncfusion support.

We have checked your reported issue, unfortunately we are not able to reproduce it in our end. And, we have considered your source changes in our end. However, we need the following details to find the exact cause of this issue.

1. Please share us the detailed description of your reported issue.
2. Share the issue replicable sample or code block to replicate in our end.

Could you please share the above details, based on that we will check and provide you a better solution quickly.

Regards,
Sangeetha M

[Sridhar-Narasimhan]

We are closing this thread now since there is no activity and long pending.