1.FIG. 2 is a block diagram showing a whole arrangement of a control system of the information processing terminal apparatus mentioned above. The data and commands input from the keyboard 12 and the screen coordinate values of the display menu instructed by the input apparatus 17 are input to a register 2 through an interface circuit 1 and read by a CPU 3. The CPU 3 executes control programs stored in a memory 51 in accordance with the input commands. Numerals 52, 53, and 54 denote memories to store table data for management of windows which will be explained hereinafter. Data of a plurality of logic screens is stored into a memory 55. The partial regions of these logic screens are displayed in each window on the CRT 10. When data is input from the keyboard 12, the data is produced or corrected for the logic screen designated in the memory 55 and the display data is sequentially transferred to a bit map processor (BMP) 4 in accordance with the content of the window management table. The BMP 4 expands the display data as a bit map in a frame memory 5. A CRT controller 6 sequentially reads out the content of the frame memory 5 and outputs this data to the CRT 10. FIG. 3 shows the relation between the logic screen and the windows. In this example, a partial region S.sub.20 of a logic screen 200, a partial region S.sub.21 of a logic screen 210, and a partial region S.sub.22 of a logic screen 220 stored in the memory 55 are displayed in a first window 20, a second window 21, and a third window 22 set in the display screen 11 of the CRT 10, respectively. The display priority of the first window 20 is the lowest and the second and third windows 21 and 22 overlap the first window 20, so that a part of the window 20 is hidden. The second window 21 is displayed in the region where it is completely included in the display region consisting of the first and third windows 20 and 22 and only a partial region 21A is displayed. Therefore, in this state, if the operator changes the display priority so that the whole region of the first window 20 can be seen, according to the conventional apparatus, the second window 21 will be completely hidden under the first and third windows as shown in FIG. 4. According to the present invention, however, when the display priority is changed, the positional relation of each window is automatically checked and if there exists any window which will be completely covered and hidden by other windows as shown in FIG. 4, this window is automatically shifted to another position, thereby enabling some portions of all of the windows to certainly appear on the screen as shown in, e.g., FIG. 5. With this method, any desired window can be designated by a cursor C as well. Therefore, the operator can sequentially change the display priorities of the windows without worrying about the positional relation among the windows. The above-mentioned automatic shifting operation of the window position can be executed by use of window management tables 30, 360, and 50 shown in FIG. 6. The first table 30 defines the relation amount the display position and size of the window and the logic screen corresponding thereto for every window defined in the display screen 11 and is formed in the memory 52. For example, as shown in FIG. 6, the first table 30 comprises: a window name 31; X coordinates 32 and Y coordinates 33 of the start points of the windows on the display screen 11, (these coordinates correspond to (X.sub.0, Y.sub.0), (X.sub.1, Y.sub.1), and (X.sub.2, Y.sub.2) in FIG. 3); size 34 in the X direction of the window; size 35 in the Y direction; a pointer 36 to the second table 360, which will be explained hereinafter; window attribute information 37 to designate the presence or absence of the window stripe, color of the window frame, and the like; data pointer 38; X coordinates 39 and Y coordinates 40 of the positions of the start points of the corresponding partial regions (S.sub.20, S.sub.21, S.sub.22 in FIG. 3) on the logic screen; and sizes 41 in the X direction and sizes 42 in the Y direction of the foregoing partial regions (col. 3, ln 6 to col. 4, ln 14).