Steps to reproduce: 
1. Create Telerik WinForms Application and add two RadForm
2. Select one of forms and set the IsMdiContainer property to true 
3. Select the child form. Open the Properties window and set the following properties at design time: 
 - WindowState to Maximized 
 - ThemeName to Windows8 or any other theme 
4. Run the application and show the child form. The child form is cut off instead maximized. 

Workaround: 
1. Reset the WindowState property at design time
2. Subscribe to the Form`s Load event and set the WindowState property 
private void RadForm2_Load(object sender, EventArgs e)
{
    this.WindowState = FormWindowState.Maximized;
}

To reproduce:

private void radButton1_Click(object sender, EventArgs e)
{ 
    StringBuilder detailsText = new StringBuilder();
    for (int i = 0; i < 10; i++)
    {
        detailsText.AppendLine("Line" + i);
    }
    detailsText.AppendLine("END");

   RadMessageBox.Show("Message", "Caption Text", MessageBoxButtons.AbortRetryIgnore, detailsText.ToString());
}

Workaround: enlarge the details section in order to fit the text: 

 FieldInfo fi = typeof(RadMessageBoxForm).GetField("detailsSectionHeight", BindingFlags.NonPublic| BindingFlags.Instance);
fi.SetValue(RadMessageBox.Instance,200); 

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;
    }
}      

Please refer to the attached project.

Workaround: maximize the form in the Load event.

To reproduce:
- Create new project.
- Make the default  form to inherit RadForm.
- Start the application and maximize the form.
- You will notice that a few pixels are displayed on the right monitor as well.

Workaround:
var screen = System.Windows.Forms.Screen.PrimaryScreen.Bounds;
this.MaximumSize = new Size(screen.Width, screen.Height);

Second Workaround:

public Form1()
{
    InitializeComponent(); 

    this.SizeChanged += Form1_SizeChanged;
}
 
private void Form1_SizeChanged(object sender, EventArgs e)
{
    if (this.WindowState == FormWindowState.Maximized)
    {
        this.Region = null;
    }
}

To reproduce:
Create a RadForm set Maxmize/Minimize box to false. Run it and try to drag the form by clicking on where the buttons used to be.

Workaround:
void MainForm_Load(object sender, EventArgs e)
{
    this.FormElement.TitleBar.MaximizeButton.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
    this.FormElement.TitleBar.MinimizeButton.Visibility = Telerik.WinControls.ElementVisibility.Collapsed;
}

There should be an option to show a help button at the titlebar part of RadForm

UPDATED: this is reproducible in a non-MDI scenario is well.

Sub New()
    InitializeComponent()
    Me.Size = New Size(500, 500)
End Sub


To reproduce:

1. Add two RadForms - a parent and a child.
2. Set the MinimumSize property of the child form at design time.
3. Use the following code snippet:

public partial class ParentForm : RadForm
{
    public ParentForm()
    {
        InitializeComponent();

        this.IsMdiContainer = true;

        ChildForm form = new ChildForm();
        form.Text = "MDI Child 1";
        form.MdiParent = this;
        form.Size = new System.Drawing.Size(600, 600);
        form.Show();
    }
}

public partial class ChildForm : Telerik.WinControls.UI.RadForm
{
    public ChildForm()
    {
        InitializeComponent();
        this.SizeChanged += ChildForm_SizeChanged;
    }
    
    private void ChildForm_SizeChanged(object sender, EventArgs e)
    {
        this.Text = "ChildForm " + this.Size.Width + " x " + this.Size.Height;
    }
}

When you run the application with version 2015.2 623, you will notice that the child form is loaded with its MinimumSize. However, in the previous version it is loaded with the expected specified Size(600, 600).

Workaround: use ShapedForm with titlebar. An alternative solution is to set the RadForm.Size property in the Shown event.

To reproduce:
- Add two buttons and a textbox to a RadForm.
- Set the AcceptButton to be the first button.
- Focus the second button and press Enter

Workaround:
protected override bool ProcessCmdKey(ref System.Windows.Forms.Message msg, System.Windows.Forms.Keys keyData)
{
    if (keyData == System.Windows.Forms.Keys.Enter)
    {
        if (this.ActiveControl is Button && this.ActiveControl != this.AcceptButton)
        {
            ((Button)this.ActiveControl).PerformClick();
            return true;
        }
        
    }

    return base.ProcessCmdKey(ref msg, keyData);
}

To reproduce: 
- Start the narrator, open a message box and close it fast.
 
Workaround:
void button_Click(object sender, EventArgs e)
{
    RadMessageBox.Instance.Shown += Instance_Shown;
    RadMessageBox.Show("test");
}

void Instance_Shown(object sender, EventArgs e)
{
    RadMessageBoxForm form = sender as RadMessageBoxForm;

    typeof(RadMessageBoxForm).GetField("accObjectCreated", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance).SetValue(form, false);
}

To reproduce: 
- Use the approach described here to localize the form: https://msdn.microsoft.com/en-us/library/y99d1cd3%28v=vs.100%29.aspx?f=255&MSPPError=-2147217396
- Open the resx file in Visual Studio.

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;

If you have a TextBox anchored to Top, Left, Right in a RadForm, the size that this TextBox gets when the form is shown may not be correct.

Workaround:
set the Dock = Fill setting after adding the controls/toolwindows in the forms

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);

If you have a RadForm that contains a RadTextBox (TextBox), set the WindowsState of this form to Maximized and add this form to an MDI Parent with RadDock which handles the forms, you will notived that you are not able to mouse select the text.

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);

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

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();
    }
}

QSF Forms&Dialogs Message box - show RadMessageBox when click on the right side of the title bar the popup dialog cannot be dragged.