diff --git a/src/ui/bigtext/bigtext.py b/src/ui/bigtext/bigtext.py
index 072283f..27aeb81 100644
--- a/src/ui/bigtext/bigtext.py
+++ b/src/ui/bigtext/bigtext.py
@@ -10,6 +10,7 @@ from PySide6.QtGui import QMouseEvent
 from PySide6.QtWidgets import *
 
 from src.ui.ScaledScrollBar import ScaledScrollBar
+from src.ui.bigtext.highlight_regex import HighlightRegex
 from src.ui.bigtext.highlight_selection import HighlightSelection
 from src.ui.bigtext.highlighted_range import HighlightedRange
 from src.ui.bigtext.highlightingdialog import HighlightingDialog
@@ -132,6 +133,12 @@ class InnerBigText(QWidget):
         self._last_double_click_time = 0
         self._last_double_click_line_number = -1
 
+        self.highlight_selected_text = HighlightRegex(
+            "",
+            is_regex=False,
+            ignore_case=True,
+            hit_background_color="d7efffc0")  # same blue as the selection hightlight, but with lower saturation
+
         self.line_click_listeners: [Callable[[int], None]] = []
 
     def keyPressEvent(self, e: QKeyEvent) -> None:
@@ -208,6 +215,7 @@ class InnerBigText(QWidget):
         if e.buttons() == Qt.MouseButton.LeftButton and e.modifiers() == Qt.KeyboardModifier.ShiftModifier:
             offset = self.to_byte_offset(e)
             self.selection_highlight.set_end_byte(offset)
+            self._update_highlight_selected_text()
             self.update()
             return
 
@@ -218,6 +226,7 @@ class InnerBigText(QWidget):
                 line: Line = self.lines[line_number]
                 self.selection_highlight.set_start(line.byte_offset())
                 self.selection_highlight.set_end_byte(line.byte_end())
+                self._update_highlight_selected_text()
                 self.update()
                 return
 
@@ -225,6 +234,7 @@ class InnerBigText(QWidget):
             offset = self.to_byte_offset(e)
             self.selection_highlight.set_start(offset)
             self.selection_highlight.set_end_byte(offset)
+            self._update_highlight_selected_text()
             self.update()
 
             line_number = self.y_pos_to_line(e.pos().y())
@@ -246,6 +256,8 @@ class InnerBigText(QWidget):
             else:
                 self.selection_highlight.set_start(offset)
                 self.selection_highlight.set_end_byte(offset)
+
+            self._update_highlight_selected_text()
             self.update()
 
     def mouseMoveEvent(self, e: QMouseEvent):
@@ -257,8 +269,10 @@ class InnerBigText(QWidget):
 
         if self.selection_highlight.end_byte != current_byte:
             self.selection_highlight.set_end_byte(current_byte)
+            self._update_highlight_selected_text()
             self.update()
             # print("-> %s,%s" %(self._selection_start_byte, self._selection_end_byte))
+
         line_number = self.y_pos_to_line(e.pos().y())
         column_in_line = self.x_pos_to_column(e.pos().x())
         if line_number < 0:
@@ -372,8 +386,20 @@ class InnerBigText(QWidget):
     def _select_all(self):
         self.selection_highlight.start_byte = 0
         self.selection_highlight.end_byte = self.model.byte_count()
+        self._update_highlight_selected_text()
         self.update()
 
+    def _update_highlight_selected_text(self):
+        start_byte=self.selection_highlight.start_byte
+        end_byte=self.selection_highlight.end_byte
+        if abs(start_byte - end_byte) < 1024:
+            query = self.model.read_range(start_byte, end_byte)
+            if query.find("\n") < 0:
+                self.highlight_selected_text.set_query(query)
+                return
+
+        self.highlight_selected_text.set_query("")
+
     def paintEvent(self, event: QPaintEvent) -> None:
         painter = QPainter(self)
         # font = "Courier New" if sys.platform == 'win32' or sys.platform == 'cygwin' else "Monospace"
@@ -398,6 +424,7 @@ class InnerBigText(QWidget):
         highlighters = self.model.highlighters()
         if self.model.get_query_highlight():
             highlighters = highlighters + [self.model.get_query_highlight()]
+        highlighters = highlighters + [self.highlight_selected_text]
         highlighters = highlighters + [self.selection_highlight]  # selection highlight should be last
 
         # draw highlights first - some characters may overlap to the next line
diff --git a/src/ui/bigtext/highlight_regex.py b/src/ui/bigtext/highlight_regex.py
index 0184aaf..543f6d7 100644
--- a/src/ui/bigtext/highlight_regex.py
+++ b/src/ui/bigtext/highlight_regex.py
@@ -29,6 +29,10 @@ class HighlightRegex(Highlight):
         else:
             return re.compile(re.escape(self.query), flags=flags)
 
+    def set_query(self, query: str) -> None:
+        self.query = query
+        self.regex = self._get_regex()
+
     def compute_highlight(self, line: Line) -> Optional[List[HighlightedRange]]:
         result = []
         # print("execute regex: %s in %s" % (self.regex, line.line()))
@@ -56,9 +60,15 @@ class HighlightRegex(Highlight):
 
     @staticmethod
     def brush(color: str) -> QBrush:
-        if re.match("[0-9a-f]{6}", color, flags=re.IGNORECASE):
+        if re.match("^[0-9a-f]{6}$", color, flags=re.IGNORECASE):
             red = int(color[0:2], 16)
             green = int(color[2:4], 16)
             blue = int(color[4:6], 16)
             return QBrush(QColor(red, green, blue))
+        if re.match("^[0-9a-f]{8}$", color, flags=re.IGNORECASE):
+            red = int(color[0:2], 16)
+            green = int(color[2:4], 16)
+            blue = int(color[4:6], 16)
+            alpha = int(color[6:8], 16)
+            return QBrush(QColor(red, green, blue, alpha))
         return QBrush()