diff --git a/libs/window.lua b/libs/window.lua
index a25aabc..fc52e61 100644
--- a/libs/window.lua
+++ b/libs/window.lua
@@ -71,6 +71,7 @@ function lib.create(name, w, h, x, y, do_not_add)
         y = y or 2,
 
         -- column-major buffer: buffer[x][y] = {char, tc, bc}
+        isFullscreen = false,
         buffer = {},
         cursorX = 1,
         cursorY = 1,
@@ -329,7 +330,9 @@ function lib.create(name, w, h, x, y, do_not_add)
             t.buffer, t.w, t.h = newbuf, nw, nh
         end
     end
-
+    function t.fullscreen(fullscreen)
+        t.isFullscreen = fullscreen or not t.isFullscreen
+    end
     function t.redraw() end -- renderer handles this elsewhere
 
     function t.setVisible(_) end
diff --git a/modules/interactions.lua b/modules/interactions.lua
index 02aecdc..733d2a0 100644
--- a/modules/interactions.lua
+++ b/modules/interactions.lua
@@ -33,24 +33,39 @@ while true do
     if data[1] == "mouse_click" then
         for indx = #_G.windows, 1, -1 do
             local win = _G.windows[indx]
+            local h= win.h
+            local w = win.w
+            local x = win.x
+            local y = win.y
+            if win.isFullscreen then
+                local sw,sh = term.getSize()
+                w = sw
+                h = sh-2
+                x=1
+                y=3
+            end
             if data[4] == 1 then
                 break
-            elseif win.x+win.w-1 == data[3] and win.y+win.h-1 == data[4] and win.decorations and win.resizable then
+            elseif x+w-1 == data[3] and y+h-1 == data[4] and win.decorations and win.resizable and not win.isFullscreen then
                 dragging = win
                 resizing = true
                 bringtofront(indx)
-            elseif ((win.y - 1 == data[4] and win.x + 1 <= data[3] and win.x + win.w >= data[3] and data[2] == 1 and win.decorations) or (win.y <= data[4] and win.x <= data[3] and win.y + win.h > data[4] and win.x + win.w > data[3] and key[keys["leftAlt"]] and win.draggable)) then
+            elseif ((y - 1 == data[4] and x + 2 <= data[3] and x + w >= data[3] and data[2] == 1 and win.decorations) or (y <= data[4] and x <= data[3] and y + h > data[4] and x + w > data[3] and key[keys["leftAlt"]] and win.draggable)) and not win.isFullscreen then
                 dragging = win
-                offsetX = win.x - data[3]
-                offsetY = win.y - data[4]
+                offsetX = x - data[3]
+                offsetY = y - data[4]
                 bringtofront(indx)
                 break
-            elseif win.y - 1 == data[4] and win.x == data[3] and win.decorations then
+            elseif y - 1 == data[4] and x == data[3] and win.decorations then
                 threading.addThread(function() win.closeRequested() end)
                 bringtofront(indx)
                 break
-            elseif win.y <= data[4] and win.x <= data[3] and win.y + win.h > data[4] and win.x + win.w > data[3] then
-                threading.addThread(function() win.clicked(data[3] - win.x + 1, data[4] - win.y + 1, data[2]) end)
+                elseif y - 1 == data[4] and x+1 == data[3] and win.decorations then
+                threading.addThread(function() win.fullscreen() end)
+                bringtofront(indx)
+                break
+            elseif y <= data[4] and x <= data[3] and y + h > data[4] and x + w > data[3] then
+                threading.addThread(function() win.clicked(data[3] - x + 1, data[4] - y + 1, data[2]) end)
                 bringtofront(indx)
                 break
             end
@@ -69,8 +84,19 @@ while true do
         else
             for indx = #_G.windows, 1, -1 do
                 local win = _G.windows[indx]
-                if win.y <= data[4] and win.x <= data[3] and win.y + win.h > data[4] and win.x + win.w > data[3] then
-                    threading.addThread(function() win.dragged(data[3] - win.x + 1, data[4] - win.y + 1, data[2]) end)
+                local h= win.h
+                local w = win.w
+                local x = win.x
+                local y = win.y
+                if win.isFullscreen then
+                    local sw,sh = term.getSize()
+                    w = sw
+                    h = sh-2
+                    x=1
+                    y=3
+                end
+                if y <= data[4] and x <= data[3] and y + h > data[4] and x + w > data[3] then
+                    threading.addThread(function() win.dragged(data[3] - x + 1, data[4] - y + 1, data[2]) end)
                     bringtofront(indx)
                     break
                 end
@@ -83,8 +109,19 @@ while true do
         else
             for indx = #_G.windows, 1, -1 do
                 local win = _G.windows[indx]
-                if win.y <= data[4] and win.x <= data[3] and win.y + win.h > data[4] and win.x + win.w > data[3] then
-                    threading.addThread(function() win.released(data[3] - win.x + 1, data[4] - win.y + 1, data[2]) end)
+                local h= win.h
+                local w = win.w
+                local x = win.x
+                local y = win.y
+                if win.isFullscreen then
+                    local sw,sh = term.getSize()
+                    w = sw
+                    h = sh-2
+                    x=1
+                    y=3
+                end
+                if y <= data[4] and x <= data[3] and y + h > data[4] and x + w > data[3] then
+                    threading.addThread(function() win.released(data[3] - x + 1, data[4] - y + 1, data[2]) end)
                     bringtofront(indx)
                     break
                 end
@@ -93,8 +130,19 @@ while true do
     elseif data[1] == "mouse_scroll" then
         for indx = #_G.windows, 1, -1 do
             local win = _G.windows[indx]
-            if win.y <= data[4] and win.x <= data[3] and win.y + win.h > data[4] and win.x + win.w > data[3] then
-                threading.addThread(function() win.scrolled(data[2], data[3] - win.x + 1, data[4] - win.y + 1) end)
+            local h= win.h
+            local w = win.w
+            local x = win.x
+            local y = win.y
+            if win.isFullscreen then
+                local sw,sh = term.getSize()
+                w = sw
+                h = sh-2
+                x=1
+                y=3
+            end
+            if y <= data[4] and x <= data[3] and y + h > data[4] and x + w > data[3] then
+                threading.addThread(function() win.scrolled(data[2], data[3] - x + 1, data[4] - y + 1) end)
                 break
             end
         end
diff --git a/startup.lua b/startup.lua
index b87907c..7f5befe 100644
--- a/startup.lua
+++ b/startup.lua
@@ -61,10 +61,21 @@ end
 local function windows()
     term.setCursorBlink(false)
     for id, win in ipairs(_G.windows) do
-        for cy = 1, win.h do
-            term.setCursorPos(win.x, win.y + cy - 1)
+        local h= win.h
+        local w = win.w
+        local x = win.x
+        local y = win.y
+        if win.isFullscreen then
+            local sw,sh = term.getSize()
+            w = sw
+            h = sh-2
+            x=1
+            y=3
+        end
+        for cy = 1, h do
+            term.setCursorPos(x, y + cy - 1)
             local line, fg, bg = "", "", ""
-            for cx = 1, win.w do
+            for cx = 1, w do
                 if win.buffer[cx] then
                     local cell = win.buffer[cx][cy]
                     if cell then
@@ -85,16 +96,16 @@ local function windows()
             term.blit(line, fg, bg)
         end
         if win.decorations then
-            term.setCursorPos(win.x, win.y - 1)
+            term.setCursorPos(x, y - 1)
             term.setTextColor(colors.white)
             term.setBackgroundColor(colors.blue)
-            term.write(string.sub("X " .. win.name .. string.rep(" ", win.w - #win.name - 2),1,win.w))
-            if win.resizable then
-                term.setCursorPos(win.x+win.w-1,win.y+win.h-1)
+            term.write(string.sub("XO " .. win.name .. string.rep(" ", w - #win.name - 3),1,w))
+            if win.resizable and not win.isFullscreen then
+                term.setCursorPos(x+w-1,y+h-1)
                 term.write("\127")
             end
         end
-        term.setCursorPos(win.x + win.cursorX - 1, win.y + win.cursorY - 1)
+        term.setCursorPos(x + win.cursorX - 1, y + win.cursorY - 1)
         nterm.setCursorBlink(win.cursorBlink)
         if win.closing then
             _G.windows[id] = nil