
This sample phab app is an example of how you can put
transparent objects on top of images.

This is not done using DBContainer or any memory context code... it is all
done just be knowing how to set widget arguments correctly.

NOTE: you need 1.14B photon (Jun22,99) or later in order for this to work
      correctly.

The most important thing is to have your base window widget with a fill
color of 'tranparent'. Then be sure to place a label widget with your
background image so that it completely hides any of the background of the
window widget. If you do not do this, then the base window will not
redraw the exposed areas correctly (it's transparent so it thinks it doesn't
have to redraw).
This is not usually a problem as your background should fill the whole
window anyway.

Then just draw as you need to on top of the label widget. The example shows
a transparent multitext widget that does blitting correctly even on the
background. it also shows some buttons ...

Another note:

The CB_FILTER callback is extremely powerful. Any container widget (which 
includes the multitext widget, as well as widgets formed into a group) can
have a callback or series of callbacks attached to raw events happening
to the widget. this is perfect for intercepting events that occur on the
widget before they get into the widget processing routines internal to the
widget.
For example, you could capture mouse click events and not pass them to the
widget. This is better described in the docs on CB_FILTER.

