diff --git a/src/gtk/toplevel.cpp b/src/gtk/toplevel.cpp
index 62cc9316b1..1931966de7 100644
--- a/src/gtk/toplevel.cpp
+++ b/src/gtk/toplevel.cpp
@@ -1262,6 +1262,15 @@ void wxTopLevelWindowGTK::GTKUpdateDecorSize(const DecorSize& decorSize)
         if (m_minWidth > 0 || m_minHeight > 0 || m_maxWidth > 0 || m_maxHeight > 0)
         {
             // update size hints, they depend on m_decorSize
+            if (!m_deferShow)
+            {
+                // if size hints match old size, assume hints were set to
+                // maintain current client size, and adjust hints accordingly
+                if (m_minWidth == m_height) m_minWidth += diff.x;
+                if (m_maxWidth == m_height) m_maxWidth += diff.x;
+                if (m_minHeight == m_height) m_minHeight += diff.y;
+                if (m_maxHeight == m_height) m_maxHeight += diff.y;
+            }
             DoSetSizeHints(m_minWidth, m_minHeight, m_maxWidth, m_maxHeight, m_incWidth, m_incHeight);
         }
         if (m_deferShow)