To reproduce:  
1. Add WindowsForm and RadRibbonBar 
2. Use this code snippet 
this.Text = string.Empty;
this.ControlBox = false;
this.radRibbonBar1.Text = "Example"; 
3. Run the project and you will see that title is visible in the Form and in the RadRibbonBar

Workaround: Use RadForm or RadRibbonForm and set the Text property.
If you use the WindowsForm, please use this code snippet: 
this.ControlBox = false;
this.radRibbonBar1.Text = "Example";
this.FormBorderStyle = FormBorderStyle.None;

To reproduce:

Create a RadRibbonForm and set its ApplicationMenuStyle to BackstageView. Start the application open the backstage, click the maximize button and then again to set the Form back to normal. You will notice that the Form cannot be set back to normal.

Workaround:

Manually change the WindowState of the Form.

this.RibbonBar.BackstageControl.BackstageElement.TitleBarElement.MaximizeButton.MouseDown +=MaximizeButton_Click;

void MaximizeButton_Click(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Maximized)
            {
                this.WindowState = FormWindowState.Normal;
            }
            else if (this.WindowState == FormWindowState.Normal)
            {
                this.WindowState = FormWindowState.Maximized;
            }
        }

To reproduce:
- Change the ApplicationMenuStyle to BackstageView.
- Add some tabs with different content.
- Start the application and change the tabs several times, you will notice that the content is not changed.

To reproduce: 
- add RadRibbonBar with several CommandTabs and private void Form1_Load(object sender, EventArgs e) { radRibbonBar1.Expanded = false; } 
- add RadButton and on its Click event use: private void radButton1_Click(object sender, EventArgs e) { radRibbonBar1.CommandTabs[0].Visibility = Telerik.WinControls.ElementVisibility.Collapsed; } 
As a result the CommandTab is collapsed but some empty space remains.

Workaround: private void radButton1_Click(object sender, EventArgs e) { radRibbonBar1.CommandTabs[0].Visibility = Telerik.WinControls.ElementVisibility.Collapsed; this.radRibbonBar1.Expanded = !this.radRibbonBar1.Expanded; this.radRibbonBar1.Expanded = !this.radRibbonBar1.Expanded; }

To reproduce:
- add RadRibbonbar with two groups;
- add several RadButtonsElements in each group;
- subscribe for the ToolTipTextNeeded event:

private void radRibbonBar1_ToolTipTextNeeded(object sender, ToolTipTextNeededEventArgs e)
{
    e.ToolTipText = sender.ToString();
}

If you hover a certain button, the tool tip for button element appears, which is correct. If you hover precisely the ribbon bar group, the correct tool tip also appears. But after that each element hovering, displays the wrong tool tip.

To reproduce:
-add RadRibbonBar (ControlDefault theme) and several tabs;
-click the ribbon bar arrow to collapse the ribbon bar;
-click the first tab to show the pop up;
-click the ribbon bar arrow once to expand the ribbon bar and click it again to collapse it;
-click the tab does not display it from the first time;

To reproduce: - add RadRibbonForm; - add one tab with RadToggleButtonElement; - subscribe to toggle button click event and use the following code: public Form1() { InitializeComponent(); RadOffice2007ScreenTipElement tip1 = new RadOffice2007ScreenTipElement(); tip1.CaptionLabel.Text = "Button1"; tip1.MainTextLabel.Text = "My Text"; RadOffice2007ScreenTipElement tip2 = new RadOffice2007ScreenTipElement(); tip2.CaptionLabel.Text = "Button2"; tip2.MainTextLabel.Text = "My Text"; radToggleButtonElement1.ScreenTip = tip1; } private void radToggleButtonElement1_Click(object sender, EventArgs e) { radRibbonBar1.Expanded = false; } When the screen is shown (hovering the toggle button), then click the button and the ribbon bar will collapse. As a result the screen tip will not disappear even on mouse move. 

Workaround: private void radToggleButtonElement1_Click(object sender, EventArgs e) { radRibbonBar1.Expanded = false; RadToggleButtonElement btn = sender as RadToggleButtonElement; if (btn != null && btn.ScreenTip != null) { PropertyInfo[] pinfos = ((ComponentBehavior)radRibbonBar1.Behavior).GetType().GetProperties(BindingFlags.NonPublic | BindingFlags.Instance); PropertyInfo barProperty = ((ComponentBehavior)radRibbonBar1.Behavior).GetType().GetProperty("ScreenPresenter", BindingFlags.NonPublic | BindingFlags.Instance); Form screenTip = barProperty.GetValue(((ComponentBehavior)radRibbonBar1.Behavior), null) as Form; screenTip.Hide(); } } 

To reproduce: Add a RadRibbonBar, add a ribbon tab with some groups and buttons. Run the application, autohide the content of the tabs, minimize the application, maximize it, open the tab the buttons are overlapping each other.

To reproduce: Add a RadRibbonBar, set it to backstage view, add a ribbon tab, run the application autohide the content of the tabs, you will notice that 2 pixels are cut off the BackstageView button

To reproduce:

Add a RadRibbonBar and a RibbonTab.
Add a control to the form (for example a textbox).
Subscribe to its LostFocus event and set the tab's visibility to collapsed in the event handler.
When you start the application click the textbox, then click the tab and you will see that the tab will hide but the content will stay visible.

To reproduce:
- add RadRibbonBar containing a Contextual tab group (composed of four tabs);
- add several RadRadioButton-s indicating which tab to be visible/collapsed:

private void radRadioButton1_ToggleStateChanged(object sender,
    Telerik.WinControls.UI.StateChangedEventArgs args)
{
    if (args.ToggleState == Telerik.WinControls.Enumerations.ToggleState.On)
    {
        this.ribbonTab1.Visibility = Telerik.WinControls.ElementVisibility.Visible;
    }
    else
    {
        this.ribbonTab1.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
    }
}

As a result, when some tab is collapsed, contextual tab group width is not changed.

======================
Workaround: set collapsed tab width to 0 and update ribbon captions's layout:

ribbonTab1.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
ribbonTab1.Size = new Size(0, this.ribbonTab1.Size.Height);

radRibbonBar1.RibbonBarElement.InvalidateMeasure(true);
radRibbonBar1.RibbonBarElement.UpdateLayout();
radRibbonBar1.RibbonBarElement.RibbonCaption.CaptionLayout.InvalidateMeasure(true);
radRibbonBar1.RibbonBarElement.RibbonCaption.CaptionLayout.UpdateLayout();

Add support for the RadRibbonBars to have their items merged while in MDI mode.

To reproduce: Add a ribbon bar with tabs and items inside. Press alt key and select some tab, in some tabs the children items KeyTIps will not appear.

To reproduce:
Create a RadRibbonForm
Add tab, groups and buttons
Add an ImageList and changed the buttons ImageKey
Minimized the ribbon
Click the tab

Workaround:
Use the image property of the button - 
buttonElement.Image = Image.FromFile(@"image.png");

If the ribbon is collapsed and the user clicks a command tab to show the ribbon, and then uses Alt-Tab or another non-mouse method to switch to another application, the ribbon menu is 'stuck' and shows above all other windows. 
Switching back to the ribbon application and clicking will hide the ribbon. Using the mouse to click to another application does not have the same issue.

Steps to reproduce:

1. Add a RadRibbonBar to a form
2. Set it to be in Backstage mode
3. Add several items in the Backstage menu
4. Set their text to contain the & sign and set UseMnemonics to true on each menu item

Run the project and press Alt you will see that the letters preceded by an & are not underscored.

RadRibbonBar, the back stage button in not exposed in style builder.

To reproduce:
- Set the Windows theme to Windows 7 Basic
- Start a RadRibbonForm and maximize it

Workaround:

void Form1_Resize(object sender, System.EventArgs e)
{
    if (this.WindowState == FormWindowState.Maximized)
    {
        this.RibbonBar.RibbonBarElement.IconPrimitive.Padding = new Padding(5, 5, 0, 0);
    }
    else
    {
        this.RibbonBar.RibbonBarElement.IconPrimitive.Padding = Padding.Empty;
    }
}

When RadGallery is collapsed there are missing scroll buttons arrow.
Also hover state of the gallery items is missing.

FIX. RadRibbonForm - theme is not applying correctly, when some changes are made to ribbon button while RadRibbonBar is collapsed.

Steps to reproduce:
1. Add button to some ribbon group.
2. Collapse the ribbon.
3. Disable this button.
4. Enable this button.
5. Expand the ribbon.

Workaround - subscribe to ExpandedStateChanged  event and reapply the theme. For example:

            this.radRibbonBar1.ExpandedStateChanged += new EventHandler(radRibbonBar1_ExpandedStateChanged);


        void radRibbonBar1_ExpandedStateChanged(object sender, EventArgs e)
        {
            this.radRibbonBar1.ElementTree.ApplyThemeToElementTree();
        }