Only half of the Select button (the top part) in Upload dialog is clickable in Material, due to the unsufficient height of the .ruFileInput element.

Workaround:
  html .rfeUploadContainer .RadUpload .ruInputs input.ruFileInput {
    height: 50px;
  }   


Steps to reproduce:
1. Open https://demos.telerik.com/aspnet-ajax/fileexplorer/examples/overview/defaultcs.aspx?skin=Material
2. Open the Upload dialog
3. Try to select a file to upload by clicking the bottom half of the button

Result: The file selection window is not opened