corrected paste sometimes leaving selection on screen

while the selection appeared on the screen, the selection was not
actually present and the document was correctly updated

the paste function was reimplemented with a clipboard mode argument,
which first clears the selection with a temporary text cursor, then the
clipboard text is inserted with the origin text cursor

for selection (middle-click) paste, the reimplemented paste function is
called with the selection clipboard mode

editbox.cpp

@@ -141,6 +141,25 @@ void EditBox::remove(void)
 }
 
 
+// function to paste text from the clipboard (and correctly update the screen)
+
+void EditBox::paste(QClipboard::Mode mode)
+{
+	QClipboard *clipboard = QApplication::clipboard();
+	QTextCursor cursor = textCursor();
+
+	// clear any selection on screen first with a temporary cursor
+	if (cursor.hasSelection())
+	{
+		QTextCursor tmpCursor = cursor;
+		tmpCursor.clearSelection();
+		setTextCursor(tmpCursor);
+	}
+
+	cursor.insertText(clipboard->text(mode));
+}
+
+
 // function to paste the current selection if supported into the program
 //
 //   - return true on success, false if selection is not supported
@@ -154,7 +173,7 @@ bool EditBox::pasteSelection(const QPoint &pos)
 		{
 			setTextCursor(cursorForPosition(pos));
 		}
-		textCursor().insertText(clipboard->text(QClipboard::Selection));
+		paste(QClipboard::Selection);
 		return true;
 	}
 	return false;

editbox.h

@@ -25,6 +25,7 @@
 #ifndef EDITBOX_H
 #define EDITBOX_H
 
+#include <QClipboard>
 #include <QPlainTextEdit>
 #include <QTextBlock>
 
@@ -37,6 +38,7 @@ class EditBox : public QPlainTextEdit
 public:
 	explicit EditBox(QWidget *parent = 0);
 	void remove(void);
+	void paste(QClipboard::Mode mode = QClipboard::Clipboard);
 	void selectAll(void);
 	void resetModified(void);
 	void captureModifiedLine(void);