Fixes null grid when moving from RIDE Log tab to Editor

Author: HelioGuilherme66

src/robotide/editor/gridcolorizer.py

@@ -37,13 +37,14 @@ def colorize(self, selection_content):
         self._coloring_task(selection_content)
 
     def _coloring_task(self, selection_content, row=0, col=0):
-        if row >= self._grid.NumberRows:
-            self._grid.ForceRefresh()
-        elif col < self._grid.NumberCols:
-            self._colorize_cell(row, col, selection_content)
-            self._coloring_task(selection_content, row, col+1)
-        else:
-            self._coloring_task(selection_content, row+1, 0)
+        if self._grid:  # For example move from RIDE Log tab to Grid
+            if row >= self._grid.NumberRows:
+                self._grid.ForceRefresh()
+            elif col < self._grid.NumberCols:
+                self._colorize_cell(row, col, selection_content)
+                self._coloring_task(selection_content, row, col+1)
+            else:
+                self._coloring_task(selection_content, row+1, 0)
 
     def _colorize_cell(self, row, col, selection_content):
         cell_info = self._controller.get_cell_info(row, col)