diff --git a/src/Classes/EditControl.lua b/src/Classes/EditControl.lua
index 63eedfa1e..2964057ad 100644
--- a/src/Classes/EditControl.lua
+++ b/src/Classes/EditControl.lua
@@ -7,6 +7,7 @@ local m_max = math.max
 local m_min = math.min
 local m_floor = math.floor
 local protected_replace = "*"
+local utf8 = require('lua-utf8')
 
 local function lastLine(str)
 	local lastLineIndex = 1
@@ -541,18 +542,10 @@ function EditClass:OnKeyDown(key, doubleClick)
 		if self.caret > 1 then
 			if ctrl then
 			-- Skip leading space, then jump word
-				while self.buf:sub(self.caret-1, self.caret-1):match("[%s%p]") do
-					if self.caret > 1 then
-						self.caret = self.caret - 1
-					end
-				end
-				while self.buf:sub(self.caret-1, self.caret-1):match("%w") do
-					if self.caret > 1 then
-						self.caret = self.caret - 1
-					end
-				end
+				self.caret = self.caret - #utf8.match(self.buf:sub(1, self.caret-1), "[%s%p]*$")
+				self.caret = self.caret - #utf8.match(self.buf:sub(1, self.caret-1), "%w*$")
 			else
-				self.caret = self.caret - 1
+				self.caret = utf8.next(self.buf, self.caret, -1) or 0
 			end
 			self.lastUndoState.caret = self.caret
 			self:ScrollCaretIntoView()
@@ -562,19 +555,11 @@ function EditClass:OnKeyDown(key, doubleClick)
 		self.sel = shift and (self.sel or self.caret) or nil
 		if self.caret <= #self.buf then
 			if ctrl then
-			-- Jump word, then skip trailing space, 
-				while self.buf:sub(self.caret, self.caret):match("%w") do
-					if self.caret <= #self.buf then
-						self.caret = self.caret + 1
-					end
-				end
-				while self.buf:sub(self.caret, self.caret):match("[%s%p]") do
-					if self.caret <= #self.buf then
-						self.caret = self.caret + 1
-					end
-				end
+			-- Jump word, then skip trailing space,
+				self.caret = self.caret + #utf8.match(self.buf:sub(self.caret), "^%w*")
+				self.caret = self.caret + #utf8.match(self.buf:sub(self.caret), "^[%s%p]*")
 			else
-				self.caret = self.caret + 1
+				self.caret = utf8.next(self.buf, self.caret, 1) or #self.buf + 1
 			end
 			self.lastUndoState.caret = self.caret
 			self:ScrollCaretIntoView()
diff --git a/src/Modules/Common.lua b/src/Modules/Common.lua
index 3c99c20d2..91877ebc8 100644
--- a/src/Modules/Common.lua
+++ b/src/Modules/Common.lua
@@ -26,6 +26,7 @@ common.curl = require("lcurl.safe")
 common.xml = require("xml")
 common.base64 = require("base64")
 common.sha1 = require("sha1")
+local utf8 = require('lua-utf8')
 
 -- Try to load a library return nil if failed. https://stackoverflow.com/questions/34965863/lua-require-fallback-error-handling
 function prerequire(...)
@@ -723,20 +724,21 @@ function formatNumSep(str)
 		end
 		local x, y, minus, integer, fraction = str:find("(-?)(%d+)(%.?%d*)")
 		if main.showThousandsSeparators then
-			integer = integer:reverse():gsub("(%d%d%d)", "%1"..main.thousandsSeparator):reverse()
+			rev1kSep = utf8.reverse(main.thousandsSeparator)
+			integer = utf8.reverse(utf8.gsub(utf8.reverse(integer), "(%d%d%d)", "%1"..rev1kSep))
 			-- There will be leading separators if the number of digits are divisible by 3
 			-- This checks for their presence and removes them
 			-- Don't use patterns here because thousandsSeparator can be a pattern control character, and will crash if used
 			if main.thousandsSeparator ~= "" then
-				local thousandsSeparator = string.find(integer, main.thousandsSeparator, 1, 2)
+				local thousandsSeparator = utf8.find(integer, rev1kSep, 1, 2)
 				if thousandsSeparator and thousandsSeparator == 1 then
-					integer = integer:sub(2)
+					integer = utf8.sub(integer, 2)
 				end
 			end
 		else
-			integer = integer:reverse():gsub("(%d%d%d)", "%1"):reverse()
+			integer = utf8.reverse(utf8.gsub(utf8.reverse(integer), "(%d%d%d)", "%1"))
 		end
-		return colour..minus..integer..fraction:gsub("%.", main.decimalSeparator)
+		return colour..minus..integer..utf8.gsub(fraction, "%.", main.decimalSeparator)
 	end)
 end