Editing Modal window (section)

=== Problems ===
{{See also|Mode_(computer_interface)#Assessment|l1=Assessment of modes in computer interfaces}}

A modal window blocks all other [[workflows]] in the top-level program until the modal window is closed, as opposed to [[modeless]] dialogs that allow users to operate with other windows.<ref name="java">{{cite web|url=http://download.oracle.com/javase/tutorial/uiswing/misc/modality.html|title=How to Use Modality in Dialogs|publisher=[[Oracle Corporation]]}}</ref> Modal windows are intended to grab the user's full attention.<ref>{{Cite web |author= |title=Modal Panel |url=http://quince.infragistics.com/Patterns/Modal%20Panel.aspx#Problem |url-status=dead |archive-url=https://web.archive.org/web/20130506101851/http://quince.infragistics.com/Patterns/Modal%20Panel.aspx#Problem |archive-date=2013-05-06 |website=quince.infragistics.com}}</ref> Users may not recognize that a modal window requires their attention, leading to confusion about the main window being non-responsive, or causing loss of the user's data input intended for the main window (see [[Mode error]]). In severe cases, the modal window appears behind another window controlled by the same program, potentially rendering the entire program unresponsive until the modal window can be located manually.

However, many interface designers have recently taken steps to make modal windows more obvious by darkening the background behind the window or allowing any mouse click outside of the modal window to force the modal window to close – a design called a [[Lightbox (JavaScript)|Lightbox]]<ref name="useit">{{Cite web|url=http://www.useit.com/alertbox/application-design.html|title=10 Best Application UIs|author=Jakob Nielsen, Alertbox}}</ref> – thus alleviating those problems. Jakob Nielsen states as an advantage of modal dialogs that it improves user awareness: "When something does need fixing, it's better to make sure that the user knows about it." For this goal, the Lightbox design provides strong visual contrast of the dialog over the rest of the visuals. The Lightbox technique is now a common tool in website design.

Modal windows are commonly implemented in ways that block the possibility to move, minimize, iconify, or push that window back, and they grab input focus, which often prevents use of a system's [[cut, copy, and paste]] facilities. This can interfere with the use of their parent applications by blocking access to other windows and data within the same application, particularly in cases where the modal window is requiring the user to input information only available in one of the windows it's covering.

For users using virtual work areas larger than their actual screens, modal windows can cause further undesirable behavior, including creating the modal on a portion of the virtual screen not currently on the display, or abruptly switching the display from what the user was working on to an entirely different section.

Modal windows tend to create an abrupt diversion of text input, especially typed input intended for other programs, into themselves. Further, modals usually interpret actuation of the [[enter key]] (or in rare cases the presence of a [[newline]] in pasted input) as a cue to accept the input and process it—or, in rare cases, may intercept a mouse click intended for a different application that has suddenly been covered. Such interception, called [[focus stealing]] (or stealing focus) can compromise privacy and security practices, as well as capture inappropriate, out-of-context input that can cause undefined, arbitrary results in the program that generated the modal window.

Depending on the specifics of implementation, modal windows can violate the [[principle of least surprise]].