## Sizers

Another supported layout mechanism is Sizers.
Sizers work by packing controls and other sizers either horizontally or vertically into boxes.

It is expected that you have some knowledge of sizers before using them in the Boa Designer. Please see the wxPython help and demo.

Here is a very basic overview of Sizer support in Boa:

- Create new sizers from the Containers/Layout page on the Palette.
- Sizer objects must be connected to container controls via the control's Sizer property.
- Non-container controls and other sizers that should be layed out within the container must first be created normally.
- A sizer item of the appropriate type should be created for all controls and sizers in the container.
- To create sizer items, use the sizer's Items property or double click on the sizer.
- Link up the controls/sizers to the sizer item via the sizer item's Window or Sizer property.
- To define the alignment and area filling properties of a sizer item, set the Flag and Proportion properties.

When the sizer is connected to a container control, the container will be decorated with coloured rectangles, Yellow indicating the area that the sizer manages and Green indicating areas of sizer items. If a sizer item is not yet linked up to it's appropriate type, it's area will contain a red-dashed box which means that it is in an incomplete state.

To navigate from a sizer item to the object that it is linked to, double click the item in the collection editor.
Navigating to a sizer item from a control in the Designer can be done by right-clicking on the selection tag and choosing Select sizer

Boa Constructor - Application Help - Sizers