Index: windows/window.c
===================================================================
--- windows/window.c	(revision 5856)
+++ windows/window.c	(working copy)
@@ -1773,6 +1773,18 @@
 		  lbuf, sizeof(lbuf));
 
     kbd_codepage = atoi(lbuf);
+
+#ifdef ONTHESPOT
+    /* Korean IME doesn't need to show the external IME composing
+     * window and it can make users less intuitive to see what they
+     * are typing. */
+    if (kbd_codepage == 949 /* Korean */) {
+	term->onthespot = 1;
+	term->onthespot_buf[0] = 0;
+    }
+    else
+	term->onthespot = 0;
+#endif
 }
 
 static void click(Mouse_Button b, int x, int y, int shift, int ctrl, int alt)
@@ -2821,10 +2833,31 @@
       case WM_IME_STARTCOMPOSITION:
 	{
 	    HIMC hImc = ImmGetContext(hwnd);
+#ifdef ONTHESPOT
+	    if (term->onthespot) {
+		COMPOSITIONFORM cf;
+		RECT rectWorkArea;
+
+		SystemParametersInfo(SPI_GETWORKAREA, 0,
+				     (void*)&rectWorkArea, 0);
+		cf.dwStyle = CFS_POINT;
+		cf.ptCurrentPos.x = 0; // drive out of screen
+		cf.ptCurrentPos.y = rectWorkArea.bottom+50;
+		ImmSetCompositionWindow(hImc, &cf);
+		ImmReleaseContext(hwnd, hImc);
+		term->onthespot_buf[0] = 0;
+		return 0;
+	    }
+#endif
 	    ImmSetCompositionFont(hImc, &lfont);
 	    ImmReleaseContext(hwnd, hImc);
 	}
 	break;
+#ifdef ONTHESPOT
+      case WM_IME_ENDCOMPOSITION:
+	term->onthespot_buf[0] = 0;
+	break;
+#endif
       case WM_IME_COMPOSITION:
 	{
 	    HIMC hIMC;
@@ -2834,8 +2867,27 @@
 	    if(osVersion.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS || 
 	        osVersion.dwPlatformId == VER_PLATFORM_WIN32s) break; /* no Unicode */
 
-	    if ((lParam & GCS_RESULTSTR) == 0) /* Composition unfinished. */
+	    if ((lParam & GCS_RESULTSTR) == 0) { /* Composition unfinished. */
+#ifdef ONTHESPOT
+		if (term->onthespot) {
+		    RECT invrect;
+
+		    /* IME_COMPOSITION carries "DBCS" character */
+		    term->onthespot_buf[0] = wParam >> 8;
+		    term->onthespot_buf[1] = wParam & 0xff;
+		    invrect.left = caret_x;
+		    invrect.top = caret_y;
+		    invrect.right = caret_x + font_width * 2;
+		    invrect.bottom = caret_y + font_height;
+		    InvalidateRect(hwnd, &invrect, TRUE);
+		}
+#endif
 		break; /* fall back to DefWindowProc */
+	    }
+#ifdef ONTHESPOT
+	    else
+		term->onthespot_buf[0] = 0;
+#endif
 
 	    hIMC = ImmGetContext(hwnd);
 	    n = ImmGetCompositionStringW(hIMC, GCS_RESULTSTR, NULL, 0);
Index: terminal.c
===================================================================
--- terminal.c	(revision 5856)
+++ terminal.c	(working copy)
@@ -1221,6 +1221,10 @@
     }
     term_schedule_tblink(term);
     term_schedule_cblink(term);
+#ifdef ONTHESPOT
+    term->onthespot = 0;
+    term->onthespot_buf[0] = 0;
+#endif
 }
 
 /*
@@ -4766,7 +4770,22 @@
 		term->curstype = cursor;
 		term->dispcursx = j;
 		term->dispcursy = i;
+#ifdef ONTHESPOT
+		if (term->onthespot && term->onthespot_buf[0]) {
+		    tchar = tchar & 0xffffff00 |
+			    (unsigned char)term->onthespot_buf[0];
+		    tattr |= ATTR_INVALID;
+		}
 	    }
+	    /* Onthespot IMEs always process DBCS characters and cursors
+	     * are always wide while composing */
+	    else if (i == our_curs_y && j == our_curs_x + 1 &&
+			term->onthespot && term->onthespot_buf[0]) {
+	    	tattr |= cursor | ATTR_INVALID;
+		term->curstype = cursor;
+		tchar = tchar & 0xffffff00 | (unsigned char)term->onthespot_buf[1];
+#endif
+	    }
 
 	    /* FULL-TERMCHAR */
 	    newline[j].attr = tattr;
Index: terminal.h
===================================================================
--- terminal.h	(revision 5856)
+++ terminal.h	(working copy)
@@ -265,6 +265,14 @@
     int wcFromTo_size;
     struct bidi_cache_entry *pre_bidi_cache, *post_bidi_cache;
     int bidi_cache_size;
+
+#ifdef ONTHESPOT
+    /*
+     * These are stuff used by the on-the-spot IME support code.
+     */
+    int onthespot;
+    char onthespot_buf[2];
+#endif
 };
 
 #define in_utf(term) ((term)->utf || (term)->ucsdata->line_codepage==CP_UTF8)
Index: putty.h
===================================================================
--- putty.h	(revision 5856)
+++ putty.h	(working copy)
@@ -609,6 +609,13 @@
 
 struct RSAKey;			       /* be a little careful of scope */
 
+#if defined(WIN32) || defined(WIN64)
+/* Korean IME doesn't need to show the external IME composing
+ * window and it can make users less intuitive to see what they
+ * are typing. */
+#define ONTHESPOT	1
+#endif
+
 /*
  * Exports from the front end.
  */