Displaying Graphics problem and buttons question

Macro GraphicsInit()
    
    Variable/G Isup, Iinf, Nsup, Ninf, Bsup, Binf           // Low and High limits
    Variable/G Iavg, Imed, Navg, Nmed, Bavg, Bmed       // Average and Median values
 
    Silent 1    
    
    DoWindow/K Prog_Window
    
    Display/W=(2,2,1145,595)/N=Prog_Window/K=1      // Creates main window
    
//          -------------------------------------------------------------------------   
//                      Displays the 3 maps:
    
    Display/HOST=Prog_Window/W=(2,22,200,200)/N=Map1; AppendImage Intensity
    ModifyImage Intensity ctab={*,*,SpectrumBlack,0}
    Label left "y position"
    Label bottom "x position"
    DrawText/W=Prog_Window 0.1,0.04,"Intensity"
    
    
    Display/HOST=Prog_Window/W=(202,22,400,200)/N=Map2; AppendImage Number
    ModifyImage Number ctab={*,*,Spectrum,0}
    Label left "y position"
    Label bottom "x position"
    DrawText/W=Prog_Window 0.31,0.04,"Number"
        
    Display/HOST=Prog_Window/W=(402,22,600,200)/N=Map3; AppendImage Brightness
    ModifyImage Brightness ctab={*,*,Spectrum,0}
    Label left "y position"
    Label bottom "x position"
    DrawText/W=Prog_Window 0.51,0.04,"Brightness"
        
//          -------------------------------------------------------------------------
//                  Displays the 3 Versus graphics:
    
    Display/HOST=Prog_Window/W=(630,15,805,190)/N=BvsN VBright vs VNum
    ModifyGraph mode=3,marker=19,rgb=(0,0,65280),msize=0.2
    Label left "Brightness"
    Label bottom "Number"
    
    Display/HOST=Prog_Window/W=(630,210,805,385)/N=BvsI VBright vs VInt
    ModifyGraph mode=3,marker=19,rgb=(0,0,65280),msize=0.2
    Label left "Brightness"
    Label bottom "Intensity"
    
    Display/HOST=Prog_Window/W=(630,405,805,580)/N=NvsI VNum vs VInt
    ModifyGraph mode=3,marker=19,rgb=(0,0,65280),msize=0.2
    Label left "Number"
    Label bottom "Intensity"
    
//          -------------------------------------------------------------------------   
//                  Displays the 3 histograms : 
    
    Display/HOST=Prog_Window/W=(25,225,175,375) /N=Histogram1 IntensityHisto
    ModifyGraph mode=5,hbFill=2,toMode=1,rgb=(17408,17408,17408), log(left)=1;DelayUpdate
    Label left "Nb of Occurences"
    Label bottom "Intensity"
    
    Display/HOST=Prog_Window/W=(225,225,375,375) /N=Histogram2 NumberHisto
    ModifyGraph mode=5,hbFill=2,toMode=1,rgb=(17408,17408,17408), log(left)=1;DelayUpdate
    Label left "Nb of Occurences"
    Label bottom "Number"
        
    Display/HOST=Prog_Window/W=(425,225,575,375) /N=Histogram3 BrightnessHisto
    ModifyGraph mode=5,hbFill=2,toMode=1,rgb=(17408,17408,17408), log(left)=1;DelayUpdate
    Label left "Nb of Occurences"
    Label bottom "Brightness"   
    
//          -------------------------------------------------------------------------
//                  Creates an input panel:     
    
    NewPanel /K=1/W=(30,400,425,560)/HOST=Prog_Window
    ShowTools
    SetDrawLayer UserBack
    SetDrawEnv linebgc= (0,15872,65280),fillfgc= (0,15872,65280);DelayUpdate
    DrawRect 526,5,6,209
    SetDrawEnv fillfgc= (65535,65535,65535), textrgb= (26112,0,0);DelayUpdate
    DrawRect 26,45,83,70
    DrawText 31,65,"Intensity"
    SetDrawEnv fillfgc= (65535,65535,65535), textrgb= (26112,0,0);DelayUpdate
    DrawRect 26,95,83,120
    DrawText 31,115,"Number"
    SetDrawEnv fillfgc= (65535,65535,65535), textrgb= (26112,0,0);DelayUpdate
    DrawRect 18,156,90,181
    DrawText 23,176,"Brightness"
    SetDrawEnv textrgb= (65535,65535,65535);DelayUpdate
    DrawText 299,36,"Avg."
    SetDrawEnv textrgb= (65535,65535,65535);DelayUpdate
    DrawText 386,36,"Med."
    ValDisplay AvgI pos={285,46}, frame=2, labelBack=(65535,65535,65535), value=Iavg
    ValDisplay MedI pos={372,46}, frame=2, labelBack=(65535,65535,65535), value=Imed
    ValDisplay AvgN pos={285,104}, frame=2, labelBack=(65535,65535,65535), value=Navg
    ValDisplay MedN pos={372,104}, frame=2, labelBack=(65535,65535,65535), value=Nmed
    ValDisplay AvgB pos={285,158}, frame=2, labelBack=(65535,65535,65535), value=Bavg
    ValDisplay MedB pos={372,158}, frame=2, labelBack=(65535,65535,65535), value=Bmed
        
                
        
    SetVariable setvar0,pos={98,39},size={123,16},title="Inf. Lim."         // Input of the values for the
    SetVariable setvar0,limits={-5,200,0.01},value= Iinf                        // Intensity, the Number and
    SetVariable setvar1,pos={142,58},size={123,16},title="Sup. Lim."            // The Brightness
    SetVariable setvar1,limits={-5,200,0.01},value= Isup
    SetVariable setvar2,pos={98,92},size={123,16},title="Inf. Lim."
    SetVariable setvar2,limits={-5,200,0.01},value= Ninf
    SetVariable setvar3,pos={142,113},size={123,16},title="Sup. Lim."
    SetVariable setvar3,limits={-5,200,0.01},value= Nsup
    SetVariable setvar4,pos={98,149},size={123,16},title="Inf. Lim."
    SetVariable setvar4,limits={-5,200,0.01},value= Binf
    SetVariable setvar5,pos={142,172},size={123,16},title="Sup. Lim."
    SetVariable setvar5,limits={-5,200,0.01},value= Bsup
    
    Button LimIntensity proc=IntensityModif, pos={446,46}, title="ChangeInt"
    Button LimNumber proc=NumberModif, pos={446,113}, title="ChangeNum"
    Button LimBrightness proc=BrightnessModif, pos={444,158}, title="ChangeBright"
    
    
    
    DoAlert 0, "Graphics are now initialized"
    
    
endmacro