diff --git a/src/edit.c b/src/edit.c
index ab67fdc68b..3c98bb8bb1 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -1411,6 +1411,11 @@ normalchar:
 	       )
 	    did_cursorhold = FALSE;
 
+	// Check if we need to cancel completion mode because the window
+	// or tab page was changed
+	if (ins_compl_active() && !ins_compl_win_active(curwin))
+	    ins_compl_cancel();
+
 	// If the cursor was moved we didn't just insert a space
 	if (arrow_used)
 	    inserted_space = FALSE;
diff --git a/src/insexpand.c b/src/insexpand.c
index c0762da908..8c15adeee4 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -192,6 +192,9 @@ static string_T	  compl_orig_text = {NULL, 0};  // text as it was before
 static int	  compl_cont_mode = 0;
 static expand_T	  compl_xp;
 
+static win_T	  *compl_curr_win = NULL;  // win where completion is active
+static buf_T	  *compl_curr_buf = NULL;  // buf where completion is active
+
 // List of flags for method of completion.
 static int	  compl_cont_status = 0;
 # define CONT_ADDING	1	// "normal" or "adding" expansion
@@ -2014,6 +2017,8 @@ ins_compl_clear(void)
     compl_matches = 0;
     compl_selected_item = -1;
     compl_ins_end_col = 0;
+    compl_curr_win = NULL;
+    compl_curr_buf = NULL;
     VIM_CLEAR_STRING(compl_pattern);
     VIM_CLEAR_STRING(compl_leader);
     edit_submode_extra = NULL;
@@ -2039,17 +2044,10 @@ ins_compl_active(void)
  * Return True when wp is the actual completion window
  */
     int
-ins_compl_win_active(win_T *wp UNUSED)
+ins_compl_win_active(win_T *wp)
 {
-    return ins_compl_active()
-#if defined(FEAT_QUICKFIX)
-        && (!wp->w_p_pvw
-# ifdef FEAT_PROP_POPUP
-            && !(wp->w_popup_flags & POPF_INFO)
-# endif
-        )
-#endif
-    ;
+    return ins_compl_active() && wp == compl_curr_win
+	&& wp->w_buffer == compl_curr_buf;
 }
 
 /*
@@ -2706,6 +2704,15 @@ ins_compl_stop(int c, int prev_mode, int retval)
     return retval;
 }
 
+/*
+ * Cancel completion.
+ */
+    int
+ins_compl_cancel(void)
+{
+    return ins_compl_stop(' ', ctrl_x_mode, TRUE);
+}
+
 /*
  * Prepare for Insert mode completion, or stop it.
  * Called just after typing a character in Insert mode.
@@ -6080,6 +6087,8 @@ ins_complete(int c, int enable_pum)
     else if (insert_match && stop_arrow() == FAIL)
 	return FAIL;
 
+    compl_curr_win = curwin;
+    compl_curr_buf = curwin->w_buffer;
     compl_shown_match = compl_curr_match;
     compl_shows_dir = compl_direction;
 
diff --git a/src/proto/insexpand.pro b/src/proto/insexpand.pro
index a9ca289db1..8529b7b6c1 100644
--- a/src/proto/insexpand.pro
+++ b/src/proto/insexpand.pro
@@ -66,4 +66,5 @@ void ins_compl_insert(int in_compl_func, int move_cursor);
 void ins_compl_check_keys(int frequency, int in_compl_func);
 int ins_complete(int c, int enable_pum);
 void free_insexpand_stuff(void);
+int ins_compl_cancel(void);
 /* vim: set ft=c : */
diff --git a/src/testdir/dumps/Test_switchwin_clear_pum_01.dump b/src/testdir/dumps/Test_switchwin_clear_pum_01.dump
new file mode 100644
index 0000000000..9005f8d853
--- /dev/null
+++ b/src/testdir/dumps/Test_switchwin_clear_pum_01.dump
@@ -0,0 +1,20 @@
+|b+0&#ffffff0@1| |b@2| |b@1> @27||+1&&|a+0&&@1| |a@2| |a@1| @27
+|~+0#4040ff13&| @4| +0#0000001#e0e0e08|b@1| @12| +0#4040ff13#ffffff0@14||+1#0000000&|~+0#4040ff13&| @35
+|~| @4| +0#0000001#ffd7ff255|b@2| @11| +0#4040ff13#ffffff0@14||+1#0000000&|~+0#4040ff13&| @35
+|~| @4| +0#0000001#ffd7ff255|a@1| @12| +0#4040ff13#ffffff0@14||+1#0000000&|~+0#4040ff13&| @35
+|~| @4| +0#0000001#ffd7ff255|a@2| @11| +0#4040ff13#ffffff0@14||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|w+3#0000000&|i|n|_|b| |[|+|]| @9|1|,|1|0| @10|A|l@1| |[+1&&|N|o| |N|a|m|e|]| |[|+|]| @5|1|,|9| @11|A|l@1
+|-+2&&@1| |K|e|y|w|o|r|d| |c|o|m|p|l|e|t|i|o|n| |(|^|N|^|P|)| |m+0#00e0003&|a|t|c|h| |1| |o|f| |4| +0#0000000&@33
diff --git a/src/testdir/dumps/Test_switchwin_clear_pum_02.dump b/src/testdir/dumps/Test_switchwin_clear_pum_02.dump
new file mode 100644
index 0000000000..39013c09fd
--- /dev/null
+++ b/src/testdir/dumps/Test_switchwin_clear_pum_02.dump
@@ -0,0 +1,20 @@
+|b+0&#ffffff0@1| |b@2| |b@1| @27||+1&&|a+0&&@1| |a@2| |a>a| @27
+|~+0#4040ff13&| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|w+1#0000000&|i|n|_|b| |[|+|]| @9|1|,|1|0| @10|A|l@1| |[+3&&|N|o| |N|a|m|e|]| |[|+|]| @5|1|,|9| @11|A|l@1
+|-+2&&@1| |I|N|S|E|R|T| |-@1| +0&&@62
diff --git a/src/testdir/dumps/Test_tabnext_clear_pum_01.dump b/src/testdir/dumps/Test_tabnext_clear_pum_01.dump
new file mode 100644
index 0000000000..6eb86e6c7d
--- /dev/null
+++ b/src/testdir/dumps/Test_tabnext_clear_pum_01.dump
@@ -0,0 +1,20 @@
+| +8#0000001#e0e0e08|[|N|o| |N|a|m|e|]| | +2#0000000#ffffff0|+| |[|N|o| |N|a|m|e|]| | +1&&@49|X+8#0000001#e0e0e08
+|a+0#0000000#ffffff0@1| |a@2| |a@1> @65
+|~+0#4040ff13&| @4| +0#0000001#e0e0e08|a@1| @12| +0#4040ff13#ffffff0@52
+|~| @4| +0#0000001#ffd7ff255|a@2| @11| +0#4040ff13#ffffff0@52
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|-+2#0000000&@1| |K|e|y|w|o|r|d| |c|o|m|p|l|e|t|i|o|n| |(|^|N|^|P|)| |m+0#00e0003&|a|t|c|h| |1| |o|f| |2| +0#0000000&@33
diff --git a/src/testdir/dumps/Test_tabnext_clear_pum_02.dump b/src/testdir/dumps/Test_tabnext_clear_pum_02.dump
new file mode 100644
index 0000000000..347767c664
--- /dev/null
+++ b/src/testdir/dumps/Test_tabnext_clear_pum_02.dump
@@ -0,0 +1,20 @@
+| +2&#ffffff0|[|N|o| |N|a|m|e|]| | +8#0000001#e0e0e08|+| |[|N|o| |N|a|m|e|]| | +1#0000000#ffffff0@49|X+8#0000001#e0e0e08
+> +0#0000000#ffffff0@74
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|-+2#0000000&@1| |I|N|S|E|R|T| |-@1| +0&&@44|0|,|1| @10|A|l@1| 
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index b2952fdc35..ac879d24ff 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -2157,4 +2157,36 @@ func Test_pum_maxwidth_multibyte()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_pum_clear_when_switch_tab_or_win()
+  CheckScreendump
+
+  let lines =<< trim END
+    inoremap <F4> <Cmd>wincmd w<CR>
+    inoremap <F5> <Cmd>tabnext<CR>
+  END
+
+  call writefile(lines, 'Xtest', 'D')
+  let buf = RunVimInTerminal('-S Xtest', {})
+
+  call term_sendkeys(buf, ":tabe\<CR>")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "Aaa aaa \<C-N>")
+  call VerifyScreenDump(buf, 'Test_tabnext_clear_pum_01', {})
+  call term_sendkeys(buf, "\<F5>")
+  call TermWait(buf, 50)
+  call VerifyScreenDump(buf, 'Test_tabnext_clear_pum_02', {})
+  call term_sendkeys(buf, "\<ESC>:tabclose!\<CR>")
+
+  call term_sendkeys(buf, ":vnew win_b\<CR>")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "Abb bbb \<C-N>")
+  call VerifyScreenDump(buf, 'Test_switchwin_clear_pum_01', {})
+  call term_sendkeys(buf, "\<F4>")
+  call TermWait(buf, 50)
+  call VerifyScreenDump(buf, 'Test_switchwin_clear_pum_02', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 30904d7c06..7bd2bb6b7b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1305,
 /**/
     1304,
 /**/