skip highlighter when query is empty

src/ui/bigtext/highlight_regex.py

@@ -35,6 +35,12 @@ class HighlightRegex(Highlight):
 
     def compute_highlight(self, line: Line) -> Optional[List[HighlightedRange]]:
         result = []
+
+        if len(self.query) == 0:
+            # query is empty - this would result in many hits and is quite expensive
+            # This happens with the highlighter we use for the selected text and maybe for the current filter query.
+            return result
+
         # print("execute regex: %s in %s" % (self.regex, line.line()))
         match_iter = re.finditer(self.regex, line.line())
         for match in match_iter: