Preserve size of wxGrid rows/columns when hiding and showing them back.

Previously, if a wxGrid row or column was hidden by setting its size to 0, its
original size was lost. Change this so that it's preserved now and can be
restored by setting the size to the special -1 value later.

Closes #14133.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72491 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/textentry.h

@@ -98,6 +98,8 @@ public:
 
     virtual void SetSelection(long from, long to) = 0;
     virtual void SelectAll() { SetSelection(-1, -1); }
+    virtual void SelectNone()
+        { const long pos = GetInsertionPoint(); SetSelection(pos, pos); }
     virtual void GetSelection(long *from, long *to) const = 0;
     bool HasSelection() const;
     virtual wxString GetStringSelection() const;