You can control the navigation path through an application by controlling the order in which the operator moves to items. Operators navigate by pressing navigational keys and by using the mouse. As the application designer, you can also initiate navigation programmatically by calling built in procedures such as GO_ITEM and GO_BLOCK from triggers and Built-in subprograms.
When Oracle Forms navigates to an item and waits for input, that item is said to have the "input focus". That is, the item is ready to accept keyboard input from the operator. Only one item in an application has the input focus at any time.
The sequence of blocks in a form and items in a block defines the default navigation order (sometimes called the TAB sequence or Tab Order.)
Blocks and items are sequenced within a form according to the order in which they appear in the Object Navigator. Each block and item has an implicit sequence number (1, 2, 3, etc.).
At form startup, Oracle Forms sets the input focus to the first item in the first block, as indicated by sequence. If the operator presses [Next Item] (the TAB key on most systems), the input focus moves to the next item in that same block. Pressing [Next Item] from the last item in the block sets focus back to the first item. Conversely, pressing [Previous Item] in the first navigable item moves the input focus to the last navigable item. Pressing [Next Block] moves the input focus to the first item in Block 2.