diff --git a/src/callback.c b/src/callback.c
index 2b308c61..1d609a16 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -1439,12 +1439,16 @@ int callback(int event, int mx, int my, KeySym key,
      mx_save = mx; my_save = my;        /* 20171218 */
      mx_double_save=mousex_snap;
      my_double_save=mousey_snap;
-     if(semaphore<2) { /* 20160425 */
+
+     /* useless code ? 20200905 */
+     /* if(semaphore<2) {
        rebuild_selected_array();
        if(lastselected==0) ui_state &=~SELECTION;
-     }
+     } */
+
      select_object(mousex, mousey, 0, 0);
      rebuild_selected_array();
+     if(lastselected==0) ui_state &=~SELECTION;
    }
    else if(button==Button2 && (state == 0)) {
      pan2(BEGIN, mx, my);
diff --git a/src/xinit.c b/src/xinit.c
index ba2c3600..ebf3b4cb 100644
--- a/src/xinit.c
+++ b/src/xinit.c
@@ -1339,6 +1339,16 @@ int Tcl_AppInit(Tcl_Interp *inter)
     set_grid(0); /* set default value specified in xschemrc as 'grid' else CADGRID */
  } /* if(has_x) */
  dbg(1, "Tcl_AppInit(): done X init\n");
+
+/* pass to tcl values of Alt, Shift, COntrol key masks so bind Alt-KeyPress events will work for windows */
+#ifndef __unix__ 
+ my_snprintf(tmp, S(tmp), "%d", Mod1Mask);
+ tclsetvar("Mod1Mask", tmp);
+ my_snprintf(tmp, S(tmp), "%d", ShiftMask);
+ tclsetvar("ShiftMask", tmp);
+ my_snprintf(tmp, S(tmp), "%d", ControlMask);
+ tclsetvar("ControlMask", tmp);
+#endif
  /*  END X INITIALIZATION */
 
  init_done=1;  /* 20171008 moved before option processing, otherwise xwin_exit will not be invoked */
diff --git a/src/xschem.tcl b/src/xschem.tcl
index a7250dbc..13ea10bf 100644
--- a/src/xschem.tcl
+++ b/src/xschem.tcl
@@ -2925,6 +2925,15 @@ proc build_windows {} {
     }
  
     bind .drw <ButtonRelease> {xschem callback %T %x %y 0 %b 0 %s}
+
+    # on Windows Alt key mask is reported as 131072 (1<<17) so build masks manually with values passed from C code 
+    if {$::OS == "Windows" } {
+      bind .drw <Alt-KeyPress> {puts xxx; xschem callback %T %x %y %N 0 0 [expr $Mod1Mask]}
+      bind .drw <Control-Alt-KeyPress> {xschem callback %T %x %y %N 0 0 [expr $ShiftMask + $Mod1Mask]}
+      bind .drw <Shift-Alt-KeyPress> {xschem callback %T %x %y %N 0 0 9 [expr $ControlMask + $Mod1Mask]}
+    }
+
+    bind .drw <KeyPress> {xschem callback %T %x %y %N 0 0 %s}
     bind .drw <KeyPress> {xschem callback %T %x %y %N 0 0 %s}
     bind .drw <KeyRelease> {xschem callback %T %x %y %N 0 0 %s} ;# 20161118
     bind .drw <Motion> {xschem callback %T %x %y 0 0 0 %s}