Setting a sheet column width to 1 when resizing by dragging

Column widths of 0 are not saved by the table and so revert back to
calculated widths when reloaded. This change sets the column width to
1 when the right border is dragged to the left border to hide columns.
By doing this, a visual indication of a hidden column is seen as the
column border is now wider by 1px.

gnucash/register/register-gnome/gnucash-header.c

@@ -470,9 +470,11 @@ gnc_header_event (GtkWidget *widget, GdkEvent *event)
         if (event->button.button != 1)
             break;
 
-
         if (header->in_resize)
         {
+            if (header->resize_col_width == 0)
+                header->resize_col_width = 1;
+
             gnc_header_resize_column
                 (header,
                  header->resize_col,