Don't check subfolders

apps/files/js/file-upload.js

@@ -768,7 +768,7 @@ OC.Uploader.prototype = _.extend({
 		// only keep non-conflicting uploads
 		selection.uploads = _.filter(selection.uploads, function(upload) {
 			var file = upload.getFile();
-			if (file.relativePath) {
+			if (file.relativePath || upload.getTargetFolder() != fileList.getCurrentDirectory()) {
 				// can't check in subfolder contents
 				return true;
 			}