diff --git a/GNUmakefile b/GNUmakefile
index 8f74207..0172f44 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -1,5 +1,7 @@
 # $Id$
 
+PREFIX = /usr/milsko
+
 ifeq ($(TARGET),)
 TARGET = $(shell uname -s)
 endif
@@ -153,13 +155,25 @@ OOL_OBJS += oosrc/widget/vulkan.o
 EXAMPLES += examples/vulkan$(EXEC)
 endif
 
-.PHONY: all format clean lib oolib examples
+.PHONY: all install format clean lib oolib examples
 
 all: lib examples
 lib: src/$(LIB)Mw$(SO)
 oolib: oosrc/$(LIB)MwOO$(SO)
 examples: $(EXAMPLES)
 
+install: lib oolib
+	mkdir -p $(PREFIX)/lib
+	mkdir -p $(PREFIX)/bin
+	mkdir -p $(PREFIX)/include
+	for i in src oosrc; do \
+		cp $$i/*.so $(PREFIX)/lib/ ; \
+		cp $$i/*.a $(PREFIX)/lib/ ; \
+		cp $$i/*.dll $(PREFIX)/bin/ ; \
+	done ; true
+	cp -rf include/Mw $(PREFIX)/include/
+	cp -rf include/MwOO $(PREFIX)/include/
+
 format:
 	clang-format --verbose -i `find oosrc src include examples tools "(" -name "*.c" -or -name "*.h" ")" -and -not -name "stb_*.h"`
 	perltidy -b -bext='/' --paren-tightness=2 `find tools -name "*.pl"`
diff --git a/README.txt b/README.txt
index 721cb76..c03cc13 100644
--- a/README.txt
+++ b/README.txt
@@ -88,6 +88,8 @@ D. MinGW-w64/GCC/Clang
 
           USE_STB_IMAGE - Use stb_image or not.
 
+          PREFIX        - Installation destination directory.
+
 
                                 Makefile targets
 
@@ -101,4 +103,6 @@ D. MinGW-w64/GCC/Clang
 
           all      - Builds lib and examples
 
+          install  - Installs Milsko to PREFIX
+
  -- Nishi  (nishi@nishi.boats) 
diff --git a/doc/index.html b/doc/index.html
index d2f8d75..40a9c44 100644
--- a/doc/index.html
+++ b/doc/index.html
@@ -2393,7 +2393,7 @@
 <pre id="Mw_Widget_ListBox_h__MwListBoxInsertMultiple">MWDECL <B><FONT COLOR="#228B22">void</FONT></B> <B><FONT COLOR="#0000FF">MwListBoxInsertMultiple</FONT></B> (
 	MwWidget handle,
 	<B><FONT COLOR="#228B22">int</FONT></B> index,
-	<B><FONT COLOR="#228B22">char</FONT></B>* <B><FONT COLOR="#228B22">const</FONT></B>* text,
+	<B><FONT COLOR="#228B22">char</FONT></B>** text,
 	<B><FONT COLOR="#228B22">int</FONT></B> count
 );</pre>
 <dl>
diff --git a/include/MwOO/Widget/ListBox.h b/include/MwOO/Widget/ListBox.h
index fe0b4fc..66a8e28 100644
--- a/include/MwOO/Widget/ListBox.h
+++ b/include/MwOO/Widget/ListBox.h
@@ -9,7 +9,7 @@ class ListBox : public MwOO::Base {
       public:
 	ListBox(const char* widget_name, MwOO::Base* parent, int x, int y, int w, int h);
 	void	    Insert(int index, const char* text);
-	void	    InsertMultiple(int index, char* const* text, int count);
+	void	    InsertMultiple(int index, char** text, int count);
 	void	    Delete(int index);
 	const char* Get(int index);
 	void	    SetBackground(const char* value);
diff --git a/oosrc/widget/listbox.cc b/oosrc/widget/listbox.cc
index c78979b..d7b0fe9 100644
--- a/oosrc/widget/listbox.cc
+++ b/oosrc/widget/listbox.cc
@@ -8,7 +8,7 @@ MwOO::ListBox::ListBox(const char* widget_name, MwOO::Base* parent, int x, int y
 void MwOO::ListBox::Insert(int index, const char* text){
 	MwListBoxInsert(this->widget, index, text);
 }
-void MwOO::ListBox::InsertMultiple(int index, char* const* text, int count){
+void MwOO::ListBox::InsertMultiple(int index, char** text, int count){
 	MwListBoxInsertMultiple(this->widget, index, text, count);
 }
 void MwOO::ListBox::Delete(int index){
diff --git a/resource/icon/error.png b/resource/icon/error.png
index 29f4329..f6ae5d5 100644
Binary files a/resource/icon/error.png and b/resource/icon/error.png differ
diff --git a/resource/icon/info.png b/resource/icon/info.png
index 3a69fa5..3c849a8 100644
Binary files a/resource/icon/info.png and b/resource/icon/info.png differ
diff --git a/resource/icon/news.png b/resource/icon/news.png
index 85462d2..4c2f065 100644
Binary files a/resource/icon/news.png and b/resource/icon/news.png differ
diff --git a/resource/icon/note.png b/resource/icon/note.png
index b1cb661..fdb1eca 100644
Binary files a/resource/icon/note.png and b/resource/icon/note.png differ
diff --git a/resource/icon/question.png b/resource/icon/question.png
index e81aaf6..19c70f8 100644
Binary files a/resource/icon/question.png and b/resource/icon/question.png differ
diff --git a/resource/icon/warning.png b/resource/icon/warning.png
index 7895894..a994b7f 100644
Binary files a/resource/icon/warning.png and b/resource/icon/warning.png differ
diff --git a/tools/readme.pl b/tools/readme.pl
index 76542b7..2a1cc0c 100755
--- a/tools/readme.pl
+++ b/tools/readme.pl
@@ -126,6 +126,8 @@ c("OPENGL        - Build OpenGL widget or not.", 60);
 l("");
 c("USE_STB_IMAGE - Use stb_image or not.", 60);
 l("");
+c("PREFIX        - Installation destination directory.", 60);
+l("");
 
 l("");
 c("Makefile targets");
@@ -139,8 +141,10 @@ l("");
 c("examples - Builds examples", 60);
 l("");
 c("all      - Builds lib and examples", 60);
-
 l("");
+c("install  - Installs Milsko to PREFIX", 60);
+l("");
+
 l(" -- Nishi  (nishi\@nishi.boats)");
 
 close(OUT);