diff --git a/src/register/basiccell.h b/src/register/basiccell.h
index c0b54a422b..0fa1608534 100644
--- a/src/register/basiccell.h
+++ b/src/register/basiccell.h
@@ -15,8 +15,15 @@ enum {
 
 
 /* The modify-verify callback is called when a user
- * makes a change to a cell.  The input is a changed string.
+ * makes a change to a cell.  
+ * The three arguments passed in are :
+ * "old", the string prior to user's attempted modification,
+ * "add", the string the user is attemptiong to add
+ *        (will be null if text is being deleted).
+ * "new", the string that would result is user's changes
+ *        are accepted.
  * It must return a string, or void if it rejects the change.
+ * The returned string will be the next cell value.
  */
 
 typedef struct _SingleCell {
@@ -29,7 +36,7 @@ typedef struct _SingleCell {
 
   char * value;   /* current value */
 
-  char * (*modify_verify) (char *);  /* modify verify callback */
+  char * (*modify_verify) (char *old, char *add, char *new);  /* modify verify callback */
 
 
 } SingleCell;
diff --git a/src/register/design.txt b/src/register/design.txt
new file mode 100644
index 0000000000..f0fee5a6d7
--- /dev/null
+++ b/src/register/design.txt
@@ -0,0 +1,65 @@
+
+Design Overview
+---------------
+The register is an infrastructure for building 
+a modular spread-sheet/matrix/array of cells,
+where each cell may have a unique/special 
+capability, e.g. to store only dates, amounts
+or text.  The register has been designed to 
+be easy to extend, modular & easy to maintain,
+and memory-efficient.  It is intended to be used
+for building financial apps and spread-sheets.
+
+The register is built of several components:
+the "cell", the "cellblock", the "cursor", the 
+"table", and the "register".
+
+The "cell" is an active cell object.  This object
+defines callbacks that are called when the user
+enters the cell (e.g. by clicking on a cell in a 
+table), when the user attempts to modify text in the
+cell (e.g. by typing in it), and when the user leaves 
+the cell (e.g. by moving to a different cell).
+
+Special-purpose cells can be created by "inheriting"
+from the cell object.  Thus, there are special-purpose
+cells for handling dates, pull-down menus, text fields,
+monetary amounts, etc.
+
+The "cellblock" is an array of active cells.  The
+cells are layed out in row-column order.  The 
+cellblock is mostly just a convenient container for
+organizing active cells in an array.
+
+The "table" is the displayed matrix.  The table is
+a complex object; it is NOT merely a cellblock.
+The table provides all of the GUI infrastructure for
+displaying a row-column matrix of strings. 
+
+The table provides one very important function
+for minimizing memory usage for large matrixes.
+It defines the notion of a "cursor".  The "cursor"
+is a cellblock (an array of active cells) that is
+moved to the location that the user is currently
+editing.  The cursor "virtualizes" cell functions;
+that is, it makes it seem to the user as if all
+cells in the table are active, when in fact the only
+cell that actually needs to be active is the one that 
+the user is currently editing.  Note that the 
+cursor "tiles" the table: when it is moved to the
+active cell, it is moved in such a way so that
+it is shifted an integer multiple of the cursor
+width and height.
+
+
+Portability Notes
+-----------------
+Note: neither the "cell", nor the "cellblock" contain
+any Motif-specific code.  They should be portable to
+other GUI's (e.g. GTK, QT).  
+
+All Motif-specific code appears in the "table".
+
+
+
+
diff --git a/src/register/main.c b/src/register/main.c
index 5f6ecd792a..5d8e1bcb83 100644
--- a/src/register/main.c
+++ b/src/register/main.c
@@ -29,10 +29,10 @@ CreateReg(Widget parent ) {
    xaccAddCell (header, cell);
    
 
-   table =  xaccMallocTable (0);
+   table =  xaccMallocTable (0, 0);
    table -> cursor = curs;
    table -> header = header;
-   xaccInitTable (table, 15);
+   xaccInitTable (table, 15, 1);
 
    xaccCreateTable (table, parent, "yodudue");
    return table;
diff --git a/src/register/pricecell.c b/src/register/pricecell.c
index f9c50a3190..d8ac1e5f61 100644
--- a/src/register/pricecell.c
+++ b/src/register/pricecell.c
@@ -4,10 +4,11 @@
 #include "price.h"
 #include "single.h"
 
-static char *  PriceMV (char * input)
+static char * 
+PriceMV (char * old, char *change, char *new)
 {
-   printf (" price mv called %s \n", input);
-   return strdup (input);
+   printf (" price mv called %s %s %s \n", old, change, new);
+   return strdup (new);
 }
 
 /* ================================================ */
diff --git a/src/register/table.c b/src/register/table.c
index 167ba70d19..7035499a23 100644
--- a/src/register/table.c
+++ b/src/register/table.c
@@ -7,21 +7,21 @@
 #include "table.h"
 
 Table * 
-xaccMallocTable (int numentries)
+xaccMallocTable (int tile_rows, int tile_cols)
 {
    Table *table;
    table = (Table *) malloc (sizeof (Table));
    table->header = NULL;
    table->cursor = NULL;
    table->entries = NULL;
-   xaccInitTable (table, numentries);
+   xaccInitTable (table, tile_rows, tile_cols);
    return table;
 }
 
 /* ==================================================== */
 
 void 
-xaccInitTable (Table * table, int numentries)
+xaccInitTable (Table * table, int tile_rows, int tile_cols)
 {
    int num_header_rows;
    int num_phys_rows;
@@ -52,20 +52,21 @@ xaccInitTable (Table * table, int numentries)
       num_phys_rows += table->header->numRows;
    }
    if (table->cursor) {
-      num_phys_rows += numentries* table->cursor->numRows;
-      num_phys_cols = table->cursor->numCols;
+      num_phys_rows += tile_rows * table->cursor->numRows;
+      num_phys_cols  = tile_cols * table->cursor->numCols;
    }
    table->num_phys_rows = num_phys_rows;
    table->num_phys_cols = num_phys_cols;
 
-   table->numEntries = numentries;
+   table->num_tile_rows = tile_rows;
+   table->num_tile_cols = tile_cols;
 
    /* create an empty table */
    table->entries = (char ***) malloc (num_phys_rows * sizeof (char **));
    for (i=0; i<num_phys_rows; i++) {
       table->entries[i] = (char **) malloc (num_phys_cols * sizeof (char *));
       for (j=0; j<num_phys_cols; j++) {
-         table->entries[i][j] = NULL;
+         table->entries[i][j] = NULL;   /* hack alert ... */
          table->entries[i][j] = strdup ("");
       }
    }
@@ -142,9 +143,15 @@ modifyCB (Widget mw, XtPointer cd, XtPointer cb)
 
    printf ("modify %d %d %s \n", row, col, cbs->verify->text->ptr);
 
+   /* reject edits by default, unless the cell handler allows them */
+   cbs->verify->doit = False;
+
    /* compute the cell location */
+   /* remove offset for the header rows */
    arr = table->header;
    if (arr) {
+      /* header rows cannot be modified */
+      if (row < arr->numRows) return;
       row -= arr->numRows;
    }
 
@@ -152,14 +159,21 @@ modifyCB (Widget mw, XtPointer cd, XtPointer cb)
    arr = table->cursor;
    if (arr) {
      row %= arr->numRows;
-     if (0 > col) return;
-     if (col >= arr->numCols) return;
+     col %= arr->numCols;
+printf ("arr %p cells %p %d %d \n", arr, arr->cells, row, col);
+printf ("cell row %p \n", arr->cells[row]);
+printf ("cell col %p \n", arr->cells[row][col]);
      if (arr->cells[row][col]) {
-        char * (*mv) (char *);
+        char * (*mv) (char *, char *, char *);
         mv = arr->cells[row][col]->modify_verify;
         if (mv) {
            char * tmp;
-           tmp = (*mv) ("haha");
+           tmp = (*mv) ("old", "haha", "new");
+
+           /* if the callback returned a non-null value, allow the edit */
+           if (tmp) {
+               cbs->verify->doit = True;
+           }
         }
      }
    }
@@ -200,7 +214,7 @@ xaccCreateTable (Table *table, Widget parent, char * name)
    if (!table) return 0;
 
    /* make sure that the table is consistent */
-   xaccInitTable (table, table->numEntries);
+   xaccInitTable (table, table->num_tile_rows, table->num_tile_cols);
 
    /* if a header exists, get alignments, widths from there */
    alignments = NULL;
diff --git a/src/register/table.h b/src/register/table.h
index cf74552201..b341204b37 100644
--- a/src/register/table.h
+++ b/src/register/table.h
@@ -13,7 +13,8 @@
 
 typedef struct _Table {
 
-  short numEntries;
+  int num_tile_rows;
+  int num_tile_cols;
 
   CellBlock *header;
   CellBlock *cursor;
@@ -22,15 +23,21 @@ typedef struct _Table {
 
   Widget reg;          /* the XbaeMatrix */
 
-  /* private data, cahces, etc. */
+  /* private data, caches, etc. */
+
+  /* the "physical" rows/cols are equal to
+   * the size of the tile times the number 
+   * of tile rows/cols
+   */
+
   int num_header_rows;
   int num_phys_rows;
   int num_phys_cols;
 } Table;
 
 
-Table     * xaccMallocTable (int numentries);
-void        xaccInitTable (Table *, int entries);
+Table     * xaccMallocTable (int tile_rows, int tile_cols);
+void        xaccInitTable (Table *, int tile_rows, int tile_cols);
 
 /* create the widget */
 Widget      xaccCreateTable (Table *, Widget parent, char * name);