The selection is shown by outlining the selected object in color. Note that the primary selection is shown with a slightly different class (currently, a somewhat fatter outline).
The primary and secondary selections can be set using the right mouse key. Clicking it close to an object makes that object the primary selection and deselects all other objects. If you keep the Shift key pressed while clicking with the right mouse key, the object closest to the mouse will be added to or deleted from the current selection.
To make it easier to select objects that are below or close to other
objects, it is convenient to understand exactly how the select key
works. In fact, when you press the right mouse button, a list of all
objects is computed that are sufficiently close to the mouse position
(the exact threshold can be set using the Select Distance slider
in the configuration panel or by the *selectDistance
resource).
This list is then sorted by increasing distance from the mouse and by
increasing depth in the drawing. If Shift was not pressed, the
current selection is now cleared. Then the first object in the list is
presented. Now, while still keeping the right mouse button pressed,
you can use the SPC key to step through the list of objects near
the mouse in order of increasing depth and distance. When you release
the right mouse button, the object is selected or deselected.
There is another trick to make selecting objects easier. When you hold down the Ctrl key while clicking the right mouse button, selection is restricted to objects of the current object type. This also works in combination with the Shift key.
When measuring the distance from the mouse position to objects, Ipe will consider objects enclosing the mouse position as being at distance zero. This has the effect that whenever you press the mouse, you will always get the filled objects below the mouse first. Sometimes (some people say `often') this is inconvenient. Ipe can be told not to consider objects as being filled while measuring the distance to the mouse, i.e. you can only select objects by clicking close to their boundary. This effect is obtained by setting the button Interior Select in the configuration panel to off.
Another way to select objects is using the select all and select type functions from the struc menu. select all selects all objects in the current drawing, while select type selects all those objects that have the same type as the currently active object type (and without deselecting anything first). Note that, consistent with the above, the keyboard shortcut of select type is the same as for select all, but with the Ctrl key added.