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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-3FE54688-2CDE-5359-9ABB-B83BFA025A81" xml:lang="en"><title>Window-owning

    13 controls and non-window-owning controls</title><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <p>Controls are similar to windows in the Window Server in that they are both

    15 bounded areas of the screen and both user interface elements. They are not

    16 synonymous, however, as a control may take up the whole of a window’s area

    17 or only part of it. For this reason controls are divided into two types: window-owning

    18 controls and non-window-owning controls. </p>

    19 <section id="GUID-A9A8EEB4-2E5D-4926-97C7-33A1A0CF67CB"><title>Window-owning controls</title> <p>A window-owning control

    20 has the same size and position as a window in the Window Server. Window-owning

    21 controls may overlap each other and may be moved around the screen within

    22 the bounds of their parent window. Dialogs, menus, toolbars and <keyword>top-level

    23 controls</keyword> are typically window-owning controls. </p> </section>

    24 <section id="GUID-E0C33F8A-9A4A-4953-A57C-E96921290086"><title>Non-window-owning controls (lodger controls)</title> <p>The

    25 majority of controls are non-window-owning. A non-window-owning control’s <keyword>extent</keyword> typically

    26 covers only part of a window on the screen: usually it is one of a number

    27 of controls within a larger <keyword>compound control</keyword> which acts

    28 as a container. </p> <p>Examples of non-window-owning controls include command

    29 buttons, text boxes and labels. </p> <p>Non-window-owning controls give greater

    30 efficiency as they require fewer resources in the Window Server and fewer

    31 process switches. They can also result in faster intialisation and redrawing

    32 because a compound control and all its non-window-owning components can be

    33 drawn with a single flush to the window server. </p> </section>

    34 <section id="GUID-22B830AC-D43C-4FB6-9C5D-1F89AD65EF8F"><title>Associated windows</title> <p>All controls have an <keyword>associated

    35 window</keyword>, whether they are window-owning or not. For a window-owning

    36 control the associated window is the window it owns. For a non-window-owning

    37 control the associated window is the window owned by the nearest window-owning

    38 control above it in the control hierarchy. </p> </section>

    39 <section id="GUID-C62985F2-84D3-44C5-BB1E-9576227FBC74"><title>See also</title> <ul>

    40 <li><p><xref href="GUID-2C443E6F-BC3D-5252-8098-9F850AA88A35.dita">Window server</xref></p></li>

    41 <li><p><xref href="GUID-E244744F-4837-5B46-8E37-4666A28BF0B7.dita">Run-time control

    42 hierarchy</xref></p></li>

    43 <li><p><xref href="GUID-B84FA223-3DFD-58C5-8CEF-C5AA73AA6290.dita">How to write

    44 controls</xref></p></li>

    45 </ul></section>

    46 </conbody></concept>