Since your custom control will eventually end up on a developer's toolbox,
it needs a bitmap to display in the developer's VB toolbox. You can let the default
ActiveX control bitmap show up in the toolbox, or you can set the
property to determine the custom control's
appearance in a developer's toolbox.
ToolBoxBitMap is like the Icon
or Picture property of other controls: You set
it by double-clicking the ToolBoxBitMap property or
clicking the Add button to the right of the property
in the Property Window of the UserControl.
Note, though, that unlike the Picture and
Icon properties, the ToolBoxBitMap's File dialog
box doesn't allow you to choose icon (.ico) files (see
Figure 13.4). Instead the ToolBoxBitMap can be a .bmp
(bitmap), .gif, .dib, .pal or .jpg file. The image size should be 16´15
pixels, or else it will be scaled by the system with unpredictable (and sometimes
FIGURE 13.4 Choosing a picture file for the UserControl's ToolBoxBitMap. Note
that the file types allowed are different from most Picture and Icon properties'