Merge branch 'textctrl-fixes'

Closes https://github.com/wxWidgets/wxWidgets/pull/546

src/msw/textctrl.cpp

@@ -1334,7 +1334,12 @@ wxTextPos wxTextCtrl::GetLastPosition() const
 {
     if ( IsMultiLine() )
     {
-        return ::GetWindowTextLength(GetHwnd());
+        int numLines = GetNumberOfLines();
+        long posStartLastLine = XYToPosition(0, numLines - 1);
+
+        long lenLastLine = GetLengthOfLineContainingPos(posStartLastLine);
+
+        return posStartLastLine + lenLastLine;
     }
 
     return wxTextEntry::GetLastPosition();
@@ -1486,13 +1491,12 @@ long wxTextCtrl::XYToPosition(long x, long y) const
 
     // Line is identified by a character position!
     long lineLength = ::SendMessage(GetHwnd(), EM_LINELENGTH, charIndex, 0);
-    // For all lines but last one we need to adjust the length
-    // to include new line character (only one because both CR and LF
-    // are virtually "displayed" at the same position).
-    if ( y < GetNumberOfLines() - 1 )
-        lineLength += 1;
 
-    if ( x >= lineLength )
+    // Notice that x == lineLength is still valid because it corresponds either
+    // to the position of the LF at the end of any line except the last one or
+    // to the last position, which is the position after the last character,
+    // for the last line.
+    if ( x > lineLength )
         return -1;
 
     return charIndex + x;