Disclosed is a method of accessing at least a first of a plurality of object owned windows simultaneously open in a graphic user interface on a computer system. For each object on a computer system, an object list is maintained. The object list includes all opened windows owned by the objects. User inputs to the computer system are monitored for a user request for a window list. Responsive to a user request for the window list, each object list is retrieved and, for objects lists having a single opened window, a window entry to the window list is listed. For object lists having a plurality of opened windows, an object entry and a plurality of window entries are added to the window list. The window list is then displayed. Window names include an owning object identifier and a description of the window. Adding a object entry and a plurality of window entries to a window list includes making the name of the object an entry and includes generating a plurality of entries for windows including descriptions of the windows. The window descriptions are placed proximate to but separate from the object name upon display of the window list.

An image information display apparatus is provided, with a plurality of address producing portions which output active signals and address signals. When the active signals and address signals are output an effective address signal is selected in response to an address deciding portion from the plurality of address signals outputted by the address producing portion in accordance with a priority order signal and the active signal inputted from outside. Accordingly read the image information is sequentially read from the address in the memory to be expressed by the effective address signal for displaying the plurality of rectangular regions. As a result the image of image parameters to display the multiwindow are reduced so that the priority order of the overlapped rectangular regions, the display positions and so on may be easily changed.

In a data processing apparatus including a single delete key, in accordance with a cursor position when the delete key is operated, a selection is made as to whether to execute a so-called "delete function" where the data indicated by the cursor is deleted, or a so-called "back delete function" where the data just before the cursor-indicated data is deleted. When the cursor indicates the data subsequent to the end data, the back delete function is executed. In other cases, the delete function is executed.

Two window ID plane storages corresponding to two frame buffers store window ID planes consisting of window ID's as window ID information for individual pixels to identify a window pixel by pixel of each frame buffer. An overlapping table storage stores an overlapping table which describes the overlapping relation among individual windows over those frame buffers. A switching section selects a window to be displayed and switches between the frame buffers pixel by pixel, in accordance with the two window ID planes and the contents of the overlapping table. The switching section then supplies the content of the selected frame buffer to a monitor.

The conversion of a drawing instruction into respective pixmap locations resident in main memory is typically performed by a host processor when an associated graphics processor cannot access the main memory. Such conversion is enhanced by employing a common pixmap accessible to the graphics processor, and arranging the host processor so that it changes a drawing instruction which references a respective pixmap into one which references the common pixmap. The changed drawing instruction is then passed to the graphic processor for conversion into respective memory locations resident in the common pixmap. Thereafter, the contents of the common pixmap is transferred to the block of main memory reserved for the respective pixmap.