Dropdown Background transparent without selection. Q2 2020

[Phillip]

Just upgraded to Q2 2020 and RadMultiColumnComboBox's dropdown background is transparent when you haven't selected an item

Looking at the differences between Q1 2020 and Q2 2020 it looks like it is tied to the CSS class .k-reset

This also happens on Telerik's demo site if you take off the Styling added from DropdownGrid.Silk.css or the class of RadMultiColumnComboBox_Silk from the RadMultiColumnComboBox.

https://demos.telerik.com/aspnet-ajax/multicolumncombobox/overview/defaultcs.aspx

/*Q1 2020*/
.k-reset {
margin: 0;
padding: 0;
border: 0;
outline: 0;
text-decoration: none;
font-size: 100%;
list-style: none;
}
/*Q2 2020*/
.k-reset {
margin: 0;
padding: 0;
border: 0;
background: 0; /*Issue overridding background*/
list-style: none;
}
/*Solution for other Developers to get around issue*/
.k-dropdowngrid-popup {
    background-color: #fff !important;
}

[Peter Milchev]

Hello Phillip,

Thank you for bringing this issue to our attention and sharing a solution with the community.

In another case we had about this it turns out that this is not a new issue but appears only when there is a Grid on the page, that brings the faulty styles.

Another easy solution for this is just adding a StyleSheetManager on the page:

<telerik:RadStyleSheetManager runat="server"></telerik:RadStyleSheetManager>

As a small token of gratitude for reporting this issue, we have updated your Telerik points.

Regards,
Peter Milchev
Progress Telerik