If you set the GenerateMember of an element to false, it generally removes 'this' from the serialized code concerning the element. However, in the cases where we have a serialized cast in the designer, the word 'this' remains. Since the element is not a member of the form/user control, we get a compile error.

TextAlign property at RadTextBoxItem is not serialized at design-time.

If you try to load a predefined theme in your project and run the project without a debugger, you may get a missing resource exception. The solution to this issue is:
Assembly lAssembly = Assembly.GetAssembly(typeof(Telerik.WinControls.Themes.Office2010Theme));   
Telerik.WinControls.ThemeResolutionService.LoadPackageResource(lAssembly, "Telerik.WinControls.Themes.Office2010.tssp");

Create a theme using the old Visual Style Builder and load this theme in your project using RadThemeManager. Let's say that this theme is for a panel. Set the ThemeName of the panel to your custom theme. Then, close the designer, clean the project and close Visual Studio. Now reopen VS and the designer - you will notice that the theme is not applied at design-time until you click on RadThemeManager or perform another action in the designer.

Let's have two controls - RadLabel and RadCheckBox and a form, anchored to Bottom, Right. Show a form containing these controls in maximized mode and you will notice that the controls' location is not correct.

The color blending feature does not work if you try to use it in the constructor of a form. It works only if you set it at Form_Load or at a later moment.

One should be able to define the exact location (in coordinates) for RadScreenTip. Currently, the screentip for the quick access buttons is shown below RadRibbonBar, but it should actually be shown under the buttons.

Host a Panel in RadHostItem and set the BackColor of the Panel. You will notice that the color set is not applied.
NOTE:   These properties should be set to the RadHostItem
//Synch inheritable properties
this.hostedControl.ForeColor = this.ForeColor;
this.hostedControl.BackColor = this.BackColor;

RadTabStrip, RadToolStrip and RadTreeView still can get the focus if validating event is cancelled.

Project Upgrade Utility tries to write in project files that do not contain any Telerik references. However, only the files that contain Telerik references should be modified and saved.

When you place several editor instances in a FlowLayoutPanel, for example RadTextBox, RadComboBox, RadDateTimePicker and set their Width to 100, this setting is lost when you run the project.

Implement a System Skinning Mechanism which enabels RadControls for WinForms to look like standard Windows Forms controls and adhere the currently set Windows theme.

When you try to set a value to the ToolTipText property of a RadItem (let's say RadButtonElement), this setting is not serialized in the designer.

A user should be able to define more RadToolTip settings such as delay, duration and colors.

When the user disables RadRibbonBarGroup and there is a RadTextBoxElement in it the textbox part of the RadTextBoxElement is not disabled.

Add PasswordChar property to RadTextBoxElement

Project Update Utility should be able to update vbproj files as well.

RadScreeTip has a wrong size the first time it is displayed. This size cannot be changed.

There is a specific case where command bindings stop working. Let's say we have a RadGridView and a binding which adds a new row in this RadGridView. If we open the context menu of RadGridView, then press ESC to close it and then execute the command binding, this binding stops working if we try to execute it further.

When the RadTextBox.Anchor is set to Bottom, Left, Right (and the AutoSize property is true), RadTextBox.Location is set to a wrong value when the form loads. This is a general RadControls issue.