If you add Excel-like checkbox filters to a RadzenDataGrid and filter across multiple columns before clicking Apply, then after the apply button is clicked the filter popups show as blank when re-opened for the first time, apart from the one on which Apply was clicked.
I can reproduce this problem on your documentation page for the Excel like filters:
Here I filtered on Employee, then on Product Name and clicked Apply on the product name pop-up. I then went back and clicked on the Employee filter button and the list loaded blank. If I close and re-open that pop-up it shows as populated correctly.
That's odd, I can definitely reproduce it. Please try these steps:
Click the "Employee" column filter and tick "Buchanan"
Click the "Product Name" column filter and tick "Chartreuse verte"
Click the Apply button on the "Product Name" pop-up
Click the "Employee" column filter and notice it's blank.
I have noticed that on a screen that auto-closes the pop-up filter window due to scrolling or low resolution this problem doesn't occur. This only happens on a screen that's large enough to keep both pop-up windows open at once.
After clicking Apply on the "Product Name" filter both pop-ups will close. After that if you immediately click on the "Employee" filter button the pop-up will be blank.
Unfortunately I don't have an easy way of recording video on my work laptop to demonstrate this.
Ahh, you're not following my steps exactly. Please don't apply the filter until the last box is ticked. e.g. tick a filter, then tick a different filter, then click apply.