diff --git a/frontend/document/koptinterface.lua b/frontend/document/koptinterface.lua
index 953b00107..24cb7e968 100644
--- a/frontend/document/koptinterface.lua
+++ b/frontend/document/koptinterface.lua
@@ -1065,7 +1065,7 @@ function KoptInterface:getWordFromReflowPosition(doc, boxes, pos)
 
     local scratch_reflowed_page_boxes = self:getReflowedTextBoxesFromScratch(doc, pageno)
     if not DEBUG.dassert(scratch_reflowed_boxes and next(scratch_reflowed_word_boxes) ~= nil, "scratch_reflowed_boxes shouldn't be nil/{}") then
-	return
+        return
     end
 
     local scratch_reflowed_word_box = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos)
@@ -1242,13 +1242,13 @@ function KoptInterface:getTextFromReflowPositions(doc, native_boxes, pos0, pos1)
 
     local scratch_reflowed_word_box0 = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos0)
     if not DEBUG.dassert(scratch_reflowed_word_box0 and next(scratch_reflowed_word_box0) ~= nil, "scratch_reflowed_word_box0 shouldn't be nil/{}") then
-	return
+        return
     end
 
     local reflowed_word_box0 = self:getWordFromBoxes(reflowed_page_boxes, pos0)
     local scratch_reflowed_word_box1 = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos1)
     if not DEBUG.dassert(scratch_reflowed_word_box1 and next(scratch_reflowed_word_box1) ~= nil, "scratch_reflowed_word_box1 shouldn't be nil/{}") then
-	return
+        return
     end
     local reflowed_word_box1 = self:getWordFromBoxes(reflowed_page_boxes, pos1)