To reproduce:
1.Add a RadButton and on its Click event, show a RadMessageBox.
2.Add a RadDropDownList .
3.Drag several themes from the toolbox and drop them onto the form (e.g. Office2010Black, Office2010Blue, TelerikMetro, Windows8)
4.Use the following code:

public Form1()
{
    InitializeComponent();

    this.radDropDownList1.Items.Add("Office2010Black");
    this.radDropDownList1.Items.Add("Office2010Blue");
    this.radDropDownList1.Items.Add("TelerikMetro");
    this.radDropDownList1.Items.Add("Windows8");

    this.radDropDownList1.SelectedIndexChanged += radDropDownList1_SelectedIndexChanged;
    this.radDropDownList1.SelectedItem = this.radDropDownList1.Items[0];
}

private void radDropDownList1_SelectedIndexChanged(object sender,
    Telerik.WinControls.UI.Data.PositionChangedEventArgs e)
{
    string itemText = this.radDropDownList1.Items[e.Position].Text;           
    ThemeResolutionService.ApplicationThemeName = itemText;
}

private void radButton1_Click(object sender, EventArgs e)
{
    RadMessageBox.Show("Some message", "Confirmation", MessageBoxButtons.OKCancel);
}

When you select a new item from the RadDropDownList, the theme for the entire application is changed. But when you click the button to show a RadMessageBox, the RadMessageBox has incorrect style for its buttons.

Workaround: set the RadMessageBox.ThemeName before showing it:

RadMessageBox.ThemeName = ThemeResolutionService.ApplicationThemeName;
RadMessageBox.Show("Some message", "Confirmation", MessageBoxButtons.OKCancel);

To reproduce:

Create a RadFrom, make it MDIParent and add MDI children Set the RightToLeft property of the MDIParent to Yes and you will see that the the left side of the child forms is a little cut off. This can be seen by comparing the distance between the end of the form and the X button.

RadMessageBox - Buttons are not arranged correctly in RTL

Workaround: use RadRibbonForm instead or set minimum and maximum size

To reproduce:

1. Open a RadForm
2. Maximize the form.
3. Restore the form. Then we can see odd line on the bottom of title bar / top of the form.  If you resize the form (make it bigger), new visible areas of form doesn't contain this weird line.

Workaround:
protected override void WndProc(ref Message m)
{
    FormWindowState currentWindowState = this.WindowState;
    base.WndProc(ref m);
    if (currentWindowState == FormWindowState.Maximized && this.WindowState== FormWindowState.Normal)
    {
      
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.SizableToolWindow;
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Sizable;
    }
}      

To reproduce:

Create a RadForm and set the property as follows:

public Form1()
{
    InitializeComponent();
    this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedToolWindow;
}

Workaround:

Set the ShowIcon property to false:

public Form1()
{
    InitializeComponent();
    this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedToolWindow;
    this.ShowIcon = false;
}

To reproduce:

Show RadMessageBox as follows:

RadMessageBox.Show(this, "מסר כלשהו", "Caption", MessageBoxButtons.OKCancel, RadMessageIcon.Error, MessageBoxDefaultButton.Button1, RightToLeft.Yes, "מסר2 כלשהו");

Open the details button and you will see that the text is כלשהו מסר2

To reproduce:

Create a RadForm and use the following code:

public Form1()
{
    InitializeComponent();

    var theme = new Telerik.WinControls.Themes.Windows7Theme();
    ThemeResolutionService.ApplicationThemeName = theme.ThemeName;// "Windows7";
    this.AllowTheming = false;
}

Start the application on Windows 7, you will see that the close/minimize/maximize buttons cannot be clicked.

Workaround:

Do not set the AllowTheming property or set it to true

Please refer to the attached screenshot.

Workaround: use a RadForm without RadRibbonFormBehavior and hide the FormElement.TitleBar.

To reproduce:

private void radButton1_Click(object sender, EventArgs e)
{
    Application.Exit();
}

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    RadMessageBox.Show("Do you want to exit?", "Confirmation", MessageBoxButtons.YesNo);
}


Workaround: Show the RadMessageBox first and then call the Application.Exit method according to the DialogResult.

DECLINED: 
When Application.Exit() is called it iterates through all forms and for each of them calls the FormClosing event. Currently the RadMessageBox is shown in a new form. So in this case during the iterating forms collection a new form is added and this causes the exception "Collection was modified; enumeration operation may not execute.". 
This is expected behavior and there are two possible solutions to prevent application from throwing exception: 
- Use this.Close(); to close the application.
- Make your checks, show RadMessageBox and after that, if needed call Application.Exit(); 

To reproduce:
public partial class Form1 : RadForm
{
    public Form1()
    {
        InitializeComponent();
        this.IsMdiContainer = true;
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        RadForm childForm = new RadForm();
      
        childForm.Text = "MDI Child " + DateTime.Now.ToShortTimeString();
        childForm.MdiParent = this;
        childForm.WindowState = FormWindowState.Maximized;
        childForm.Show();
    }
}

To reproduce:
- Create blank WinForms RadForm Application.
- Set WindowState property to Maximized.
- Add RadGroupBox to the form. Set equal space on all sides.
- Anchor the group box to all sides.
- Launch application - spacing around outside of group box is incorrect.
-  Restore form to normal size - spacing around group box is incorrect.

Workaround:
radGroupBox1.Dock = DockStyle.Fill;
radGroupBox1.GroupBoxElement.Margin = new Padding(20);

For the time being to show the grid I would recommend you to use an empty RadStatusStrip.

To reproduce: 
1. Use the following code snippet: 
RadMessageBox.Show("RadMessageBox Some message box text", "Caption", MessageBoxButtons.OK, RadMessageIcon.Error);
2. The text is not aligned with the icon

When you have a RadPageViewPage with a TableLayoutPanel inside a RadForm, by changing the theme the TableLayoutPanel is shrinking.

Pleas find attached a sample project.

Workaround: use a ShapedForm instead of RadForm/RadRibbonForm.

To reproduce:
- Add form and set its AutoScroll property to true. add some controls so the scrollbars appear.
- Dock the form in a smaller window as a MDI child.

Workaround -  Use scrollable panel.

Broken in Q2 2015

Workaround: get current dpi settings and resize the form
float dpiX = 0;
float dpiY = 0;
Graphics graphics = this.CreateGraphics();
dpiX = graphics.DpiX;
dpiY = graphics.DpiY;

this.Width *= dpiX / 96;
this.Height *= dpiY / 96;

To reproduce: 
- Set the MaximizedBounds property so the form takes the entire right part of the screen, the change the windows state at runtime:
private void radButton1_Click(object sender, EventArgs e)
{
    setFormMaximizedBounds(200);
}

private void radButton2_Click(object sender, EventArgs e)
{
    setFormMaximizedBounds(-1);
}
private void setFormMaximizedBounds(int distance)
{
    if (distance >= 0)
    {
        var ownerScreen = Screen.FromControl(this);
        var workingArea = ownerScreen.WorkingArea;
        var x = workingArea.X + distance;
        var y = workingArea.Y;
        var w = workingArea.Width - distance;
        var h = workingArea.Height;
        this.MaximizedBounds = new Rectangle(x, y, w, h);
    }
    else
    {
        this.MaximizedBounds = new Rectangle(0, 0, 0, 0);
    }

    if (this.WindowState == FormWindowState.Maximized)
    {
        this.WindowState = FormWindowState.Normal;
        this.WindowState = FormWindowState.Maximized;
    }
}

How to reproduce: 
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        this.IsMdiContainer = true;
        this.Load += Form1_Load;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        RadForm form = new RadForm();
        form.Text = "MDI Child 1";
        form.MdiParent = this;
        form.Show();
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        RadForm activeChild = this.ActiveMdiChild as RadForm;
        if (activeChild == null)
        {
            MessageBox.Show("no active form child found!");
            return;
        }
        else
        {
            SaveAsBitmap(activeChild, activeChild + ".Jpeg");
            MessageBox.Show("Screen Captured successfully.");
        }
    }

    public void SaveAsBitmap(Form form, string fileName)
    {
        SaveFileDialog dialog = new SaveFileDialog();
        dialog.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif";
        if (dialog.ShowDialog() == DialogResult.OK)
        {
            Bitmap bmp = new Bitmap(form.Width, form.Height);
            form.DrawToBitmap(bmp, new Rectangle(0, 0, form.Width, form.Height));
            bmp.Save(dialog.FileName, ImageFormat.Jpeg);
        }
    }
}

Workaround:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        this.IsMdiContainer = true;
        this.Load += Form1_Load;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        RadForm form = new RadForm();
        form.Text = "MDI Child 1";
        form.MdiParent = this;
        form.Show();
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        RadForm activeChild = this.ActiveMdiChild as RadForm;
        if (activeChild == null)
        {
            MessageBox.Show("no active form child found!");
            return;
        }
        else
        {
            SaveAsBitmap(activeChild, activeChild + ".Jpeg");
            MessageBox.Show("Screen Captured successfully.");
        }
    }

    public void SaveAsBitmap(Form form, string fileName)
    {
        Bitmap bmpScreenshot = new Bitmap(form.Bounds.Width, form.Bounds.Height, PixelFormat.Format32bppArgb);
        Graphics gfxScreenshot = Graphics.FromImage(bmpScreenshot);
        Point pt = form.Parent.PointToScreen(form.Location);
        gfxScreenshot.CopyFromScreen(pt.X, pt.Y, 0, 0, form.Bounds.Size, CopyPixelOperation.SourceCopy);
        SaveFileDialog saveImageDialog = new SaveFileDialog();
        saveImageDialog.Title = "Select output file:";
        saveImageDialog.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif";
        if (saveImageDialog.ShowDialog() == DialogResult.OK)
        {
            bmpScreenshot.Save(saveImageDialog.FileName, ImageFormat.Png);
        }
    }
}