allegro Start emphasize it have the Datatip ICON, But i can't get it on my toolbar. or Maybe i set it wrong.
The dynamic display of datatips can be controlled by setting the variable: focus_followmous.
[we can find it on the User Preferences ]
its characteristics inculde:
Unset:
shows datatips only when the Allegro canvas is in foucs, that it, only when the Allegro window is active.
Allegro_Derived:
Show datatips when the Allegro derived window is in focus, such as show element, reports and so on.
Anywhere:
Shows datatips regardless of the focus. For example, datatip will appear on pointing to an element on the Allegro canvas even if any other application window is active.

The skill of navigating design elements.
it was based on the base elements such as cline segments, pins and vias cannot be parents of other elements, they are the building blocks of hierarchical elements. For a symbol with a shape containing a void,  for example, the hierarchy may span five levels. The segment comprising the void has a hierarchy of Other Seg - void - Shape - Symbol - Component.m if we enable more than one base or hierarchical element in the Find window pane, the base element determines the hierarchical elements you may choose. we can use pre-defined hot keys:
Ctrl-Tab for all base elements (Note: The Ctrl-Tab key is unavailable when you select by window.)
Tab for all hierarchical elements(Note: The Tab key is unavailable when you select by window, which chooses only top-level hierarchical elements)
The Find window pane to disable unwanted elements.

another way:
Using the Selection Set (pop-up menu);  when we click the right-key, the pop-up menus show us the Selection-Set. we can select the elements by the "Select by Polygon", "Select by Lasso", "Select on Path", "Object Brower".
We need to know the Narrwo Select and Toggle Select. For example, If we had choose the multipile elements, we could click the right_click on mouse, the pop-up menu, "Selection-set ---> Toggle Selection", we can cancel the selected element had been choosen or adds it to the selection set. (we notice the a minus sign or plus sign).
How to modify the elements in the selection set using the following:
Left-click:
Clears previous selection set and adds highlighted elements at the mouse location to the selection set. if nothig is selectable at this location, clears previous selection set.
Shift + left-click:
Adds highlighted element at the mouse location to the selection set.
Ctrl + Left-click:
Adds the highlighted element at the mouse location if not already in the selection set. Removes the highlighted elemnt from the selection set if the selection set already contains it.
Selection by window:
Clears previous selection set. Adds elements enabled in the Find window pane and that overlap the window to the selection set.
Shift + Select by window:
Adds elements enabled in the Find window pane and that overlap the window to the selection set.
Ctrl + Select by window :
@) enabled in the Find window pane.
@) overlapping the window.
@) already tin the selection set.

Choosing Design elements with Superfilter or with the Object Browser

Pop-Up menu:
there are some sub-menus:
@Quick Utilities>>>>>>>>>
It allows access to frequently used functions, such as Undo, Design Parameters, and Grids, and are independent of the selection set contents.
@Application Mode>>>>>>>>>
We can choose the Application Mode (General Edit, Interconnect Flow Planner(IFP), Etch Edit, Placement Edit, or NONE)
@Superfilter >>>>>>>>>>>>
it confines your work to a particular element type, such as all net, and disables the Find window pane.
@Customize >>>>>>>>>>>>
Enable Single Click Execution lets commands execute with a single rather than double-click, such as add connect in etchedit application mode
Disable Automatic Drag Operations initiates select by window rather than slide functionality
Enable Shape Selection through Shape Fill
Reset to Defaults.
@Selection Set
Clear All Selections empties the selection set.
Object Browser lets you search for elements by name or by property.
Select appears only if elements are available to choose at the current mouse position.
Narrow Select lets you refine your selection when multiple elements have been chosen during an editiong session.
Toggle Selection lets you further refine the elements in the selection set after you select by window. Clicking an element with a minus sign next to ti removes it from the selection set; clicking an element with a plus sign adds it to the selection set.