diff --git a/doc/CpptrajManual.pdf b/doc/CpptrajManual.pdf
index 3b7084f674..b6d9d5db1d 100644
Binary files a/doc/CpptrajManual.pdf and b/doc/CpptrajManual.pdf differ
diff --git a/doc/cpptraj.lyx b/doc/cpptraj.lyx
index b5c516d5d1..9108771209 100644
--- a/doc/cpptraj.lyx
+++ b/doc/cpptraj.lyx
@@ -31287,7 +31287,7 @@ stfcdiffusion mask <mask> [out <file>] [time <time per frame>]
 \end_layout
 
 \begin_layout LyX-Code
-              [mask2 <mask>] [lower <distance>] [upper <distance>]
+              [mask2 <mask> [lower <distance>] [upper <distance>]]
 \end_layout
 
 \begin_layout LyX-Code
diff --git a/src/Action_STFC_Diffusion.cpp b/src/Action_STFC_Diffusion.cpp
index 67aa64101e..54ab3309c4 100644
--- a/src/Action_STFC_Diffusion.cpp
+++ b/src/Action_STFC_Diffusion.cpp
@@ -19,7 +19,7 @@ Action_STFC_Diffusion::Action_STFC_Diffusion() :
 
 void Action_STFC_Diffusion::Help() const {
   mprintf("\tmask <mask> [out <file>] [time <time per frame>]\n"
-          "\t[mask2 <mask>] [lower <distance>] [upper <distance>]\n"
+          "\t[mask2 <mask> [lower <distance>] [upper <distance>]]\n"
           "\t[nwout <file>]) [avout <file>] [distances] [com]\n"
           "\t[x|y|z|xy|xz|yz|xyz]\n"
           "  Calculate diffusion of atoms in <mask>\n");
@@ -95,6 +95,12 @@ Action::RetType Action_STFC_Diffusion::Init(ArgList& actionArgs, ActionInit& ini
     calcType_ = DIST;
     // See if imaging is to be performed.
     image_.InitImaging( !(actionArgs.hasKey("noimage")) );
+  } else if (actionArgs.Contains("lower")) {
+    mprinterr("Error: 'lower' requires 'mask2'\n");
+    return Action::ERR;
+  } else if (actionArgs.Contains("upper")) {
+    mprinterr("Error: 'upper' requires 'mask2'\n");
+    return Action::ERR;
   }
 
   if (calcType_ != DEFAULT)
diff --git a/src/DataSet_string.cpp b/src/DataSet_string.cpp
index a710279fbc..9269d22a05 100644
--- a/src/DataSet_string.cpp
+++ b/src/DataSet_string.cpp
@@ -38,7 +38,7 @@ void DataSet_string::WriteBuffer(CpptrajFile &cbuffer, SizeArray const& pIn) con
     cbuffer.Printf(format_.fmt(), "NoData");
   else {
     // Protect against CpptrajFile buffer overflow.
-    if (Data_[pIn[0]].size() >= CpptrajFile::BUF_SIZE) {
+    if (format_.Width() >= (int)CpptrajFile::BUF_SIZE) {
       // FIXME: Data sets should not have to worry about spaces in format strings.
       if (format_.fmt()[0] == ' ') cbuffer.Printf(" ");
       cbuffer.Write(Data_[pIn[0]].c_str(), Data_[pIn[0]].size());
diff --git a/src/Version.h b/src/Version.h
index 0f298b530c..e324438b53 100644
--- a/src/Version.h
+++ b/src/Version.h
@@ -12,7 +12,7 @@
  * Whenever a number that precedes <revision> is incremented, all subsequent
  * numbers should be reset to 0.
  */
-#define CPPTRAJ_INTERNAL_VERSION "V4.14.10"
+#define CPPTRAJ_INTERNAL_VERSION "V4.14.11"
 /// PYTRAJ relies on this
 #define CPPTRAJ_VERSION_STRING CPPTRAJ_INTERNAL_VERSION
 #endif