For the time being the following workaround can be used:
		<telerik:RadFileExplorer ID="RadFileExplorer1" runat="server" Width="230px" Height="430px" DisplayUpFolderItem="true"
			ExplorerMode="FileTree">
		</telerik:RadFileExplorer>
		<script>
			Telerik.Web.UI.RadFileExplorer.prototype._onTreeContextMenuItemClicked = function (sender, args) {
				var treeNode = args.get_node();
				var menuItem = args.get_menuItem().get_value();
				switch (menuItem) {
					case "Rename":
						treeNode.startEdit();
						var nodeInput = treeNode.get_inputElement();
						if (!this._allowFileExtensionRename) {
							var item = this._createItemFromTreeViewNode(treeNode);
							if (!item.isDirectory())
								nodeInput.value = $T.FileExplorerHelper.stripExtension(item);
						}
						this._attachFileNameValidator(nodeInput);
						var treeUL = sender.get_childListElement();
						this._treeKeyDownDelegate = Function.createDelegate(this, this._treeKeyDown);
						if (treeUL) $telerik.addHandler(treeUL, "keydown", this._treeKeyDownDelegate, true);
						break;
					case "NewFolder":
						if (!this._isNodeADirectory(treeNode)) {
							treeNode = treeNode.get_parent();
						}
						var nodeValue = treeNode.get_value();
						this.createNewDirectory(nodeValue);
						break;
					case "Delete":
						var selItems = sender.get_selectedNodes();
						var delItem = new Array();
						for (var i = 0; i < selItems.length; i++) {
							var currItem = this._createItemFromTreeViewNode(selItems[i]);
							delItem.push(currItem);
						}
						this.deleteItem(delItem);
						break;
					case "Upload":
						this._showUploadWindow();
						break;
					case "Copy":
						var selectedItem = null;
						if (!treeNode.get_selected()) {
							selectedItem = this._createItemFromTreeViewNode(treeNode);
						}
						this._copy("tree", selectedItem);
						break;
					case "Paste":
						var pasteItem = this._createItemFromTreeViewNode(treeNode);
						this._paste(pasteItem);
						break;
				}
			}
		</script>

TreeView context menu remains visible when a permission alert is shown. I should be hidden like the Grid contect menu is.

Video:

https://screencast-o-matic.com/watch/crlYQMV2dzP

Steps to reproduce:

1. Copy a file from the Grid in RadFileExplorer

2. Right click over the same directory in the TreeView and select Paste

Result:

have found similar issue :  http://www.telerik.com/support/pits.aspx#/details/Issue=5296
which look like has been fixed, but unfortunately for following case it doesn't:
We still have performance issue, in following situations:
   - when content root folder contains few (1-5) subfolders
   - one of subfolder contains lot of (200-500) sub-subfolders 

then first time RadFileExplorer  loading to long (aproximatelly 3-5min). after some researching has been found that problem in the method:  

     private bool HasSubFolders(string virtualPath);

which instead of simply check that folder isn't empty (exist any one file or directory)  always construct complete version of the subtree (in the example above - subtree contains 200-500 subfolders, each of them checking for content, permission etc - that is why it takes time). Probable to check that node  HasSubFolders, RadFileExplorer  could execute new virtual method of the FileSystemContentProvider bool HasSubFolders. In that case: FileSystemContentProvider (or inherited classes) will decide that Folder contains SubFolders.

It is not possible to select a Toolbar item in RadFileExplorer on Enter press if the control is used in Lightweight render mode.

Steps to reproduce:

1. Open https://demos.telerik.com/aspnet-ajax/fileexplorer/examples/keyboardsupport/defaultcs.aspx

2. Press "Ctrl+f2" to focus RadFileExplorer

3. Press "Shift+1" to focus its toolbar

4. Use the Arrow keys to navigate between to Toolbar items

5. Press Enter over a button (e.g. Upload)

Result: The command is not triggered

Workaround: The issue is not reproducible in Classic render mode.

It is not possible to navigate between ContextMenu items with the arrow keys when the Keyboard support is enabled.

The ThreeView remains the focused element even after the ContextMenu is shown and using the arrow keys navigates through the tree nodes instead of the ContextMenu items.

Steps to reproduce.

1. Click somewhere on the page and press "F" for focus FileExplorer
   
2. Press "T" to focus TreeView
3. Press "C" to show tree context menu
4. Pres Up/down arrow to navigate through the context menu items

Result: The navigation occurs in the three instead of the Context menu

            <telerik:RadFileExplorer ID="RadFileExplorer1" Height="380px" Width="750px"
                AllowPaging="false" EnableCopy="true" runat="server">
                <Configuration EnableAsyncUpload="true" SearchPatterns="*.*" UploadPaths="~/Images/" DeletePaths="~/Images/" ViewPaths="~/Images/"></Configuration>
            <KeyboardShortcuts
                FocusFileExplorer="F"
                FocusAddressBar="A"
                FocusToolBar="B"
                FocusTreeView="T"
                ContextMenu="C"  
                />

FileExplorer does not scroll its tree properly to the programatically selected folders.

Steps to reproduce:

1. Set a nested folder with a long path programatically:

fileExplorer.set_currentDirectory("/images/AAA/FolderA1/FolderA2/FolderA3/FolderA4/FolderA5")

2. Select another nested folder programatically:

fileExplorer.set_currentDirectory("/images/BBB/FolderB1/FolderB2/FolderB3/FolderB4/FolderB5")

Result: The second folder is selected, but the TreeView does not properly scroll into view containing it.

A JavaScriptError is thrown when FileExplorer with enabled AsyncUplaod is used for multiple files uploading in IE. The message of the error is:
JavaScript runtime error: Object doesn't support property or method 'get_allowMultiRowSelection'

Steps to reproduce:
1. Open http://demos.telerik.com/aspnet-ajax/fileexplorer/examples/asyncupload/defaultcs.aspx in IE10
2. Open the FileExplorer's Upload dialog
3. Select 2 or more files for upload
4. Click the Upload button

Result: A JavaScript error is thrown.

When users quickly select different folders in the TreeView and content is still loading, the caching mechanism of FileExplorer fails and loads incorrect data to the last selected folder. 

There is a scroll and the Upload button is partially hidden when the Bootstrap skin is used in Classic render mode:

FileExplorer does not persist the scrolling position of its tree pane when a folder from the tree is selected in LW (and both horizontal and vertical sroll-bars are shown).

video - http://screencast.com/t/gG0l8Vbf7

Reproduction code:

protected void Page_Load(object sender, EventArgs e)
{
    RadToolBarDropDown dropDown = new RadToolBarDropDown("PageSize");
       
    dropDown.CssClass = "perPageDropDown";
    dropDown.EnableImageSprite = false;
    // dropDown.Text = GetGlobalResourceObject("Insight", "Per pagina")
    // dropDown.ToolTip = GetGlobalResourceObject("Insight", "Per pagina")
    FileExplorer1.ToolBar.Items.Add(dropDown);
}

<telerik:RadFileExplorer RenderMode="Lightweight" runat="server" ID="FileExplorer1" Width="595px" Height="350px"
    AllowPaging="true" PageSize="10">
    <Configuration EnableAsyncUpload="true" ViewPaths="~/"
        UploadPaths="~/" DeletePaths="~/"></Configuration>
</telerik:RadFileExplorer>

Changing the paths of FileExplorer dynamically leads to popping an alert message for "non-existing folder" even in no InitialPath has been set. After closing the alert RadFileExplorer gets bound successfully.

video: http://screencast.com/t/NSGjo8moC5eL

The bug is introduced in version 2015.2.729.


Steps to reproduce:
1. Run the following code:
ASP:
<telerik:RadFileExplorer ID="RadFileExplorer1" runat="server">
     <Configuration ViewPaths="~/" />
</telerik:RadFileExplorer>
<telerik:RadButton ID="Btn1" runat="server" Text="Change ViewPath" OnClick="Btn1_Click"></telerik:RadButton>

CS:
protected void Btn1_Click(object sender, EventArgs e) {
    RadFileExplorer1.InitialPath = "/Bin";
    RadFileExplorer1.Configuration.ViewPaths = new string[] { "~/Bin" };
}

2. Click the "Change ViewPath" button

Result: FileExplorer shows an alert with message "You are navigating to a non-existing folder or do not have proper permissions..."

A workaround is to disable the embedded jQuery and use an older version (for example, 1.11.1 which is the previous version the suite used): https://docs.telerik.com/devtools/aspnet-ajax/controls/scriptmanager/disabling-the-embedded-jquery

A workaround is to disable the embedded jQuery and use an older version (for example, 1.11.1 which is the previous version the suite used): https://docs.telerik.com/devtools/aspnet-ajax/controls/scriptmanager/disabling-the-embedded-jquery

Repro steps:

1. put a file explorer on the page
2. right click a file in it and select Rename
3. enter a new name, click OK

Expected: file is renamed

Actual: Firefox throws TypeError: access to strict mode caller function is censored

Sample markup

        <telerik:RadFileExplorer RenderMode="Lightweight" runat="server" ID="FileExplorer1" Width="520px" Height="310px">
            <Configuration ViewPaths="~/images" UploadPaths="~/images"
                DeletePaths="~/images"></Configuration>
        </telerik:RadFileExplorer>

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

If the AsyncUpload control is enabled in the FileExplorer when  and the user uploads more that 1 file, the FileExplorer throws a JavaScript error with the following message:

TypeError: this.control.get_allowMultiRowSelection is not a function