My mouse scrambles the screen in 132x50 text mode?
 Problem with mouse driver
──────────────────────────────────────────────────────────────────────────────

 Most mouse drivers assume that any text mode over 80 columns by 25 rows is a
 graphics mode and so attempts to use a graphics cursor. Unfortunately this
 is not the case.

 The following steps may help you to resolve the problem:

 1. Refer to your video card hardware documentation for a text video mode for
    a large text screen number in hexadecimal, for example, the Cirrus Logic
    CL542X has support for 132 text columns by 43 text rows, which is mode 54
    in hexadecimal.

 2. Create a text file that contains the following text:

        n test.com      
        a 100           
        MOV ax, 00<n>   
        INT 10          
        MOV ax, 40      
        MOV es, ax      
        MOV di, 0049    
        MOV al, 3       
        STOSB           
        INT 20          
                        
        rcx             
        12              
        w               
        q               


    where <n> on the third line is the video mode that you wish to use, in
    the case of the Cirrus Logic 542X is 54 ie. MOV ax, 0054    

 Please note that although the above is not case sensitive, the placement of
 the blank line is very important - so don't remove it.

 3. Save the file as HELPMRD.DEB

 4. At a DOS Prompt type:

        DEBUG < HELPMRD.DEB

 This will create a small TEST.COM program that you may run before MrDebug to
 set the video mode and mouse up for use with MrDebug. In most cases this
 will cure the problem of garbage on the screen - if only we could do this
 for our code!