Use the attached project to reproduce.

Workaround:
private void RadForm1_SizeChanged(object sender, EventArgs e)
{
    if (this.WindowState == FormWindowState.Normal)
    {
        this.SizeChanged -= RadForm1_SizeChanged;
        this.Size = new Size(this.Size.Width + 1, this.Size.Height + 1);
        this.Size = new Size(this.Size.Width - 1, this.Size.Height - 1);

        this.SizeChanged += RadForm1_SizeChanged;
    }
}

To reproduce:
1. Open the demo app on a remote machine
2. Click on the local machine to move the focus to it 
3. Hold down Alt key
4. Click on the demo app on the remote machine
5. Release the Alt key => the keytips are shown, while they shouldn't as KeyDown was not on that machine

To reproduce: add 3 ribbon tabs at design time and use the following code snippet:

public Form1()
{
    InitializeComponent(); 
}

private void InsertTabs()
{
    for (int i = 1; i <= 5; i++)
    {
        var index = radRibbonBar1.CommandTabs.IndexOf(this.ribbonTab3);
        radRibbonBar1.CommandTabs.Insert(index, new RibbonTab(string.Format("Tab {0}", i.ToString())));
    }
}

private void Form1_Load(object sender, EventArgs e)
{
    InsertTabs();
}

Workaround: insert the tabs in the form's constructor.

To reproduce:
- Add ribbon bar to a form and set its IsMdiContainer property to true.
- Add an MDI child with a ribbon bar and minimize it.

Workaround: set the AutoScaleMode property of UserControl to None.

If I left-click on one of tab header, the related tab expand itself showing all the contained items.
But, if I expand the tab using the mouse right button, the tab expand itself but it appears blank!

Workaround:

private void radRibbonBar1_MouseDown(object sender, MouseEventArgs e)
{
    RibbonTab tab = this.radRibbonBar1.ElementTree.GetElementAtPoint(e.Location) as RibbonTab;
    if (tab!=null && e.Button== System.Windows.Forms.MouseButtons.Right)
    {
        tab.IsSelected = true;
    }
}

How to reproduce: set a size in the designer, when the form loads its size will not be the same as the one set

Workaround: set the size in the Load event of the ribbon form

private void Form_Shown(object sender, EventArgs e)
{
	this.Size = new Size(600, 600);
}

To reproduce:

public partial class Form2 : RadRibbonForm
{
    public Form2()
    {
        InitializeComponent(); 

        this.WindowState = FormWindowState.Maximized;
        this.radRibbonBar1.ApplicationMenuStyle = ApplicationMenuStyle.BackstageView;
        this.AllowAero = false;         
        this.Icon = Properties.Resources.WinFormsIcon;     
    }
}

Workaround1: set AllowAero property to true if it is possible.
Workaround2: this.radRibbonBar1.RibbonBarElement.RibbonCaption.MouseMove += RibbonCaption_MouseMove;
private void RibbonCaption_MouseMove(object sender, MouseEventArgs e)
{
    if (e.Button == System.Windows.Forms.MouseButtons.Left && this.WindowState== FormWindowState.Maximized)
    {
        this.WindowState = FormWindowState.Normal;
        this.Location = new Point(this.Location.X,e.Location.Y);
    }
}

Workaround:

public Form1()
{
    InitializeComponent();
     
    this.radRibbonBar1.KeyTipShowing+=radRibbonBar1_KeyTipShowing;
}

private void radRibbonBar1_KeyTipShowing(object sender, CancelEventArgs e)
{
    RadButtonElement b = sender as RadButtonElement;
    if (b!=null && b.Enabled==false)
    {
        e.Cancel = true;
    }
}

To reproduce:
Add RadRibbonForm and change the theme(for example to WIndows8Theme). Run the project. The system buttons are covered by the fill of RadRibbonBarElement.

Workaround:
Set the DrawFill property of RadRibbonBarElement to false.
this.RibbonBar.RibbonBarElement.DrawFill = false;

To reproduce:
- Set the theme and show the help button.

Workaround:
Hide the fill and the border in Visual Style builder

To reproduce:
1.Create a new Visual C# -> Telerik Windows Forms Application
2.Drag a RadRibbonBar control onto RadForm1
3.Create a single tab "First Tab" (otherwise you cannot collapse the ribbon)
4.Drag a button onto the form and add the following code to the click event handler:
RibbonTab tab = new RibbonTab("Test");
this.radRibbonBar1.CommandTabs.Add(tab);
tab.IsSelected = true;
5.You should end up with something like the attached png file.
6.Run the project and click the button. You should see the new tab is created and selected.
7.Close the project and run it again. This time, collapse the ribbon before clicking the button. No new tab is visible on the ribbon. Even if you click on the [First Tab] to show the full ribbon.
8.Click the expand ribbon button on the right and the new tab will then appear.

Workaround:
bool isExpanded = this.radRibbonBar1.Expanded;
this.radRibbonBar1.Expanded = true;
RibbonTab tab = new RibbonTab("Test " + this.radRibbonBar1.CommandTabs.Count); 
this.radRibbonBar1.CommandTabs.Add(tab);
tab.IsSelected = true;
this.radRibbonBar1.Expanded = isExpanded;

To reproduce:

1. Add a RadRibbonBar with a RadDropDownListElement and some other elements.
2. Use the following code:

for (int i = 0; i < 5; i++)
{
    RadListDataItem item = new RadListDataItem();
    item.Text = "Item" + i;
    this.radDropDownListElement1.Items.Add(item);
}
this.radRibbonBar1.EnableKeyMap = true;
this.radDropDownListElement1.KeyTip = "S";         
this.radDropDownListElement1.DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDownList; 
3. Press Alt, then 2. You will see the key tips for the drop down and its sibling items. 
4. Press S. You are expected to be navigated to the RadDropDownListElement, but are not. 

Here it is illustrated the behavior: http://screencast.com/t/Qmvqufznjt

Please refer to the attached gif file.

Workaround: close manually the popup by calling the this.radSplitButtonElement1.DropDownMenu.ClosePopup(Telerik.WinControls.UI.RadPopupCloseReason.Mouse) method.

Add support for MDI list menu item.  

I have a RadGalleryElement in my RadRibbonBar.  It has both a minimum and maximum row count of four, and currently contains 6 items.  I have "selection" enabled for the Gallery.  The selection states persist for the first row of items, but do not for my second row.

With particular cultures the alt key is used for specific symbols and this is why the user should be able to use one of the alt key for symbols and the other one for the key tips.

To reproduce:
public RadRibbonForm1()
{
    InitializeComponent();
    radRibbonBar1.Expanded = false;
}     

private void button1_Click(object sender, EventArgs e)
{
    if (ribbonTab2.Visibility == Telerik.WinControls.ElementVisibility.Visible)
    {
        ribbonTab2.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
    }
    else
    {
        ribbonTab2.Visibility = Telerik.WinControls.ElementVisibility.Visible;
    }
}

Workaround:
private void button1_Click(object sender, EventArgs e)
{
  
    this.radRibbonBar1.RootElement.SuspendLayout();
    if (ribbonTab2.Visibility == Telerik.WinControls.ElementVisibility.Visible)
    {
        ribbonTab2.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
    }
    else
    {
        ribbonTab2.Visibility = Telerik.WinControls.ElementVisibility.Visible;
    }
    this.radRibbonBar1.RootElement.ResumeLayout(false);          
}

To reproduce: 
1. Add a RadRibbonBar and a RadButtonElement in one of the groups.
2. Set the RadButtonElement.UseCompatibleTextRendering property is set to false.
3. Set the RadButtonElement.Enabled property to false.

You will notice that the text is hardly read compared to version Q2 2014.

Workaround: Currently, the possible solution is to set the RadButtonElement.UseDefaultDisabledPaint property to false and subscribe to the EnabledChanged event where you can modify the ForeColor in order to make it gray when the button is disabled and apply a gray scaled image. 

To rperoduce:
- Set the themes as follows:
var theme = new Office2010BlackTheme();
new Telerik.WinControls.RadControlSpy.RadControlSpyForm().Show();
ThemeResolutionService.ApplicationThemeName = theme.ThemeName;

this.radRibbonBar1.ElementTree.EnableApplicationThemeName = false;
this.radRibbonBar1.ThemeName = "ControlDefault";

- Start and collapse the ribbon tabs. 
- Click on a tab to show its controls.

Workaround: Use the ApplyThemeToControlTree method instead of settig the ApplicationThemeName property.
ThemeResolutionService.ApplyThemeToControlTree(this, "Windows");