Don't divide by zero.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20921 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

contrib/src/fl/rowlayoutpl.cpp

@@ -433,6 +433,9 @@ void cbRowLayoutPlugin::ApplyLengthRatios( cbRowInfo* pRow )
     // look like total of mLetRatio's is 1.0, thus original
     // len. ratios are _preserved_:
 
+    if (pcntSum == 0.0)
+        pcntSum = 1.0;
+
     double unit = freeSpc / pcntSum;
 
     bool haveSquished = FALSE;