in our application we use fileuploadbuttonasynchronous in combination with drag'n drop.
At least we told our users to upload files always with drag'n drop from the windows file explorer.
For fileuploadbuttonasynchronous we defined the property "fileextensions" with a list of the allowed file extensions.
But with drag'n drop from the windows file explorer users can drop any file with any arbitrary extension on this upload button. So it is possible to upload files with a "wrong" extension.
Is it possible to suppress the uploading of "wrong" file extensions?