Consider scrollbars overlapping the scrolled window at its edges

This assumes that the scrollbar are at the right and bottom edge.
Hopefully no platform will change this.

This commit should avoid the situation where the selection to scroll to
is hidden behind the scrollbar.

src/document.h

@@ -273,17 +273,17 @@ struct Document {
             sw->GetClientSize(&canvasw, &canvash);
             if ((layoutys > canvash || layoutxs > canvasw) && s.g) {
                 wxRect r = s.g->GetRect(this, s, true);
-                if (r.y < originy || r.y + r.height > maxy || r.x < originx ||
-                    r.x + r.width > maxx) {
+                if (r.y < originy || r.y + r.height > maxy - wxSYS_HSCROLL_Y || r.x < originx ||
+                    r.x + r.width > maxx - wxSYS_VSCROLL_X) {
                     int curx, cury;
                     sw->GetViewStart(&curx, &cury);
                     sw->SetScrollbars(1, 1, layoutxs, layoutys,
-                                      r.width > canvasw || r.x < originx
+                                      r.width > canvasw - wxSYS_VSCROLL_X || r.x < originx
                                           ? r.x
-                                          : r.x + r.width > maxx ? r.x + r.width - canvasw : curx,
-                                      r.height > canvash || r.y < originy
+                                          : r.x + r.width > maxx - wxSYS_VSCROLL_X ? r.x + r.width - canvasw + wxSYS_VSCROLL_X: curx,
+                                      r.height > canvash - wxSYS_HSCROLL_Y || r.y < originy
                                           ? r.y
-                                          : r.y + r.height > maxy ? r.y + r.height - canvash : cury,
+                                          : r.y + r.height > maxy - wxSYS_HSCROLL_Y ? r.y + r.height - canvash + wxSYS_HSCROLL_Y : cury,
                                       true);
                     RefreshReset();
                     return true;