The Scrollbar widget is a horizontal or vertical scrollbar, depending on the value of the Orientable:orientation property.

Its position and movement are controlled by the adjustment that is passed to or created by scrollbarNew. See Adjustment for more details. The Adjustment:value field sets the position of the thumb and must be between Adjustment:lower and Adjustment:upper - Adjustment:page-size. The Adjustment:page-size represents the size of the visible scrollable area. The fields Adjustment:step-increment and Adjustment:page-increment fields are added to or subtracted from the Adjustment:value when the user asks to move by a step (using e.g. the cursor arrow keys or, if present, the stepper buttons) or by a page (using e.g. the Page Down/Up keys).

CSS nodes

plain code

scrollbar[.fine-tune]
╰── contents
    ├── [button.up]
    ├── [button.down]
    ├── trough
    │   ╰── slider
    ├── [button.up]
    ╰── [button.down]

GtkScrollbar has a main CSS node with name scrollbar and a subnode for its contents, with subnodes named trough and slider.

The main node gets the style class .fine-tune added when the scrollbar is in 'fine-tuning' mode.

If steppers are enabled, they are represented by up to four additional subnodes with name button. These get the style classes .up and .down to indicate in which direction they are moving.

Other style classes that may be added to scrollbars inside ScrolledWindow include the positional classes (.left, .right, .top, .bottom) and style classes related to overlay scrolling (.overlay-indicator, .dragging, .hovering).