# Selecting Rulers, Shapes Or Instances

Rulers, images, shapes or instances can be selected by either clicking on the shape, instance, ruler or image in "Select" mode or by dragging a selection rectangle with the left mouse button pressed. In this case, all objects inside the selection rectangle will be selected.

Pressing the Shift key in addition to selecting shapes, instances or other objects will extend the current selection. Pressing Ctrl key will remove the given objects from the selection.

For layout objects (shapes and instances), it is possible to select the objects through the hierarchy or on the level of the current cell only (top level objects only). By default, objects are selected through the hierarchy. That means, objects in child cells can be selected. By extending the selection over multiple instances of a cell, the same object can be selected multiple times. While editing objects inside a child cell may be a desirable feature, this can lead to confusing effects in the end. Hence, it may to more intuitive to only work on top level, i.e. on the current cell. To enable this mode, check the "Select Top Level Objects Only" menu item in the "View" menu or the same in the edit mode options dialog (F3).

In top-level only mode, instances of cells are selected only if the cells have a visual appearance. This is the case, if they contain at least one shape on a visible layer for example. If they are empty with respect to the visible layers, they cannot be selected. If the cell's box is shown, because the hierarchy levels shown are confined a sufficiently small interval, the cell instances will always be selected.

Images and rulers are simple objects not embedded in a hierarchy and can be selected by clicking at them or enclosing them in the selection box.

Object properties can be inspected or edited (if allowed) by opening the properties dialog. To edit or inspect the properties of selected objects, choose "Properties" from the "Edit" menu. A dialog will open which shows the properties for the first selected object. To proceed to the next object push the "Next" button, to go back to the previous object push the "Previous" button.

Depending on the application mode, the properties of the selected objects may be edited too. To apply changes to the current object, choose "Apply". To apply the changes and close the dialog, choose "Ok". To apply the changes to the current object and all other selected objects of the same kind, choose "Apply To All" (if applicable). To close the dialog without applying any changes, choose "Cancel".

"Apply To All" will try to apply the changes in some smart way to other objects. For example, for boxes, and change of the box dimensions will be applied in the same way (same shift in the four directions) than for the current object. If the width of a path has been changed, the same width will be applied to all other paths and so forth.

For shapes and instances, the "User properties" can be edited too. "User properties" are arbitrary properties attached to shapes and instances. They consist of a key (preferably a number for GDS2 compatibility) and a value (preferably a string in GDS2). Multiple properties of that kind can be attached to one object. User properties can be edited by pushing the "User Properties" button which will open a dialog that allows editing of the properties. If this dialog is closed with "Ok", the user properties will be kept, but applied to the layout object only after pressing "Apply"/"Ok" or "Apply To All". The latter will apply the new properties to all other shapes of the same kind.

Finally, for shapes and instances, the "Instantiation" button will show the instantiation path of the shapes or instances.

The layer of a shape cannot be changed through the properties dialog. To move a shape to a different layer, use "Change Layer" from the "Selection" sub-menu in "Edit".