Standards

Absolute Positioning and Z-Indexing

Absolute positioning is used in Open MCT in the main envelope interface to handle layout and draggable pane splitters, for elements that must be dynamically created and positioned (like context menus) and for buttons that are placed over other elements, such as a plot's zoom/pan history and reset buttons. When using absolute positioning, follow these guidelines:

• Don't specify a z-index if you don't have to.
• If you must specify a z-index, use the lowest number you that prevents your element from being covered and puts it at the correct level per the table below.

Type	Description	Z-index Range
Base interface items	Base level elements	0 - 1
Primary pane	Elements in the primary "view area" pane	2
Inspector pane, splitters	Elements in the Inspector, and splitters themselves	3
More base interface stuff	Base level elements	4 - 9
Treeview	Lefthand treeview elements	30 - 39
Help bubbles, rollover hints	Infobubbles, and similar	50 - 59
Context, button and dropdown menus	Context menus, button menus, etc. that must overlay other elements	70 - 79
Overlays	Modal overlay displays	100 - 109
Event messages	Alerts, event dialogs	1000