diff --git a/clients/riscos/riscosclient.cpp b/clients/riscos/riscosclient.cpp
index 8741ff2bda..32948ee047 100644
--- a/clients/riscos/riscosclient.cpp
+++ b/clients/riscos/riscosclient.cpp
@@ -355,7 +355,7 @@ RiscOSResizeMid::paintEvent(QPaintEvent * e)
 RiscOSResizeMid::mouseMoveEvent(QMouseEvent * e)
 {
   QRect g = client_->geometry();
-  g.setHeight(e->globalPos().y());
+  g.setBottom(e->globalPos().y());
 
   QSize adjustedSize = client_->adjustedSize(g.size());