diff --git a/kitty/glfw.c b/kitty/glfw.c
index c3cca60b6..90ec2a343 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -87,7 +87,7 @@ strip_csi_(const char *title, char *buf, size_t bufsz) {
             } break;
             case IN_CSI: {
                 if (!(('0' <= ch && ch <= '9') || ch == ';' || ch == ':')) {
-                    if (ch >= ' ' && ch != DEL) *(dest++) = ch;
+                    if (ch > DEL) *(dest++) = ch;  // UTF-8 multibyte
                     state = NORMAL;
                 }
             } break;
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index 2e6b1243c..ac834b771 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -560,9 +560,10 @@ class TestDataTypes(BaseTest):
         def q(x, y=''):
             self.ae(y or x, strip_csi(x))
         q('test')
-        q('a\x1bbc', 'ac')
+        q('a\x1bbc', 'abc')
         q('a\x1b[bc', 'ac')
         q('a\x1b[12;34:43mbc', 'abc')
+        q('a\x1b[12;34:43\U0001f638', 'a\U0001f638')
 
     def test_single_key(self):
         from kitty.fast_data_types import GLFW_MOD_KITTY, GLFW_MOD_SHIFT, SingleKey