Tabbed document interface (TDI) or a Tab is one that allows multiple documents to be contained within a single window, using tabs as a navigational widget for switching between sets of documents. It is an interface style most commonly associated with web browsers, web applications, text editors, and preference panes.
The name TDI implies similarity to the Microsoft Windows standards for multiple document interfaces (MDI) and single document interfaces (SDI), but TDI does not form part of the Microsoft Windows User Interface Guidelines. Compliance to Microsoft User Interface Guidelines
An example of Mozilla Firefox 3.5 with two tabs open. Each tab shows a different webpage, thus saving screen space by not requiring multiple windows. There is some debate about how the TDI fits in with the Microsoft Windows User Interface Guidelines. In many ways the Workbook window management model most closely resembles TDI. However this is a relatively recent addition to the Windows User Interface Guidelines, and most developers still prefer to view SDI or MDI as the primary document models for Windows. Comparison to SDI
Because the tabbed document interface holds many different documents logically under one window, it keeps the primary operating system interface free of the clutter that would be created by a large number of small child windows. Another advantage is that sets of related documents can be grouped within each of several windows. Tabbed web browsers often allow users to save their browsing session and return to it later. Disadvantages
Geany text editor with vertically-oriented tabs, showing the large number of documents that can be accommodated Although the tabbed document interface does allow for multiple views under one window, there are problems with this interface. One such problem is dealing with many tabs at once. When a window is tabbed to a certain number that exceeds the available area of the monitor, the tabs clutter up (this is the same problem as with SDI but moved to another place in the user interface). Multi-row tabs are a second issue that will appear in menu dialogs in some programs. Some prefer to have many tabs open, and some programs help making these compact yet identifiable, while normally dealing with multiple rows of tabs in one window is seen to have two disadvantages: * It creates excess window clutter, unless it is limited to about 3 rows that can be scrolled by the mouse wheel. * It complicates what should be an easy-to-read dialog, and at the same time makes it easier to see the titles of many tabs at once. Finding a specific tab in a 3 or 4 level tabular interface can be difficult for some people. Part of the issue with this difficulty lies in the lack of any sorting scheme. Without such tabs can be strewn about without any sense of order, thus looking for a tab provides no meaningful understanding of a position to a tab relative to other tabs. Additionally, the clutter created by multiple tabs can create a dialog that is unusually small, with the tabs above it dominating the window. Thus, although tabbed windows are adequate in environments where there is a minimal necessity for tabs (around ten tabs or less), this scheme does not scale, and alternate methods may be required to address this issue. Among the methods for addressing the problems of the scalability of many tabs: * group tabs by dragging/moving them, and or freeze their position, and then reduce the width of individual tabs, so that more can fit within the available area, including multiple tab rows, and * change the color of selected tabs or according to source, along with the use of favicons for identification and tooltips on mouseover * introduce scrolling to enable tabs to occupy a non-visible region of the screen * introduce sections through any of various means, to spread tabs out to multiple areas * introduce...