diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 4c62dac7d0..4f35df0245 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -9690,6 +9690,10 @@ static void f_win_move_separator(typval_T *argvars, typval_T *rettv, EvalFuncDat
   if (wp == NULL || wp->w_floating) {
     return;
   }
+  if (!win_valid(wp)) {
+    emsg(_(e_cannot_resize_window_in_another_tab_page));
+    return;
+  }
 
   int offset = (int)tv_get_number(&argvars[1]);
   win_drag_vsep_line(wp, offset);
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index 734ece73b4..56b1af5ff5 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -99,6 +99,15 @@ bool is_mouse_key(int c)
          || c == K_X2DRAG
          || c == K_X2RELEASE;
 }
+
+static win_T *dragwin = NULL;  ///< window being dragged
+
+/// Reset the window being dragged.  To be called when switching tab page.
+void reset_dragwin(void)
+{
+  dragwin = NULL;
+}
+
 /// Move the cursor to the specified row and column on the screen.
 /// Change current window if necessary. Returns an integer with the
 /// CURSOR_MOVED bit set if the cursor has moved or unset otherwise.
@@ -135,7 +144,6 @@ int jump_to_mouse(int flags, bool *inclusive, int which_button)
   static bool on_winbar = false;
   static int prev_row = -1;
   static int prev_col = -1;
-  static win_T *dragwin = NULL;         // window being dragged
   static int did_drag = false;          // drag was noticed
 
   win_T *wp, *old_curwin;
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 336dd50292..dd8952ea3f 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -2610,7 +2610,12 @@ static void cmdline_search_stat(int dirc, pos_T *pos, pos_T *cursor_pos, bool sh
       len += 2;
     }
 
-    memmove(msgbuf + STRLEN(msgbuf) - len, t, len);
+    size_t msgbuf_len = STRLEN(msgbuf);
+    if (len > msgbuf_len) {
+      len = msgbuf_len;
+    }
+    memmove(msgbuf + msgbuf_len - len, t, len);
+
     if (dirc == '?' && stat.cur == maxcount + 1) {
       stat.cur = -1;
     }
diff --git a/src/nvim/testdir/test_mapping.vim b/src/nvim/testdir/test_mapping.vim
index bde3624adf..fd840e46fe 100644
--- a/src/nvim/testdir/test_mapping.vim
+++ b/src/nvim/testdir/test_mapping.vim
@@ -1048,6 +1048,30 @@ func Test_mouse_drag_mapped_start_select()
   set mouse&
 endfunc
 
+func Test_mouse_drag_statusline()
+  set laststatus=2
+  set mouse=a
+  func ClickExpr()
+    call Ntest_setmouse(&lines - 1, 1)
+    return "\<LeftMouse>"
+  endfunc
+  func DragExpr()
+    call Ntest_setmouse(&lines - 2, 1)
+    return "\<LeftDrag>"
+  endfunc
+  nnoremap <expr> <F2> ClickExpr()
+  nnoremap <expr> <F3> DragExpr()
+
+  " this was causing a crash in win_drag_status_line()
+  call feedkeys("\<F2>:tabnew\<CR>\<F3>", 'tx')
+
+  nunmap <F2>
+  nunmap <F3>
+  delfunc ClickExpr
+  delfunc DragExpr
+  set laststatus& mouse&
+endfunc
+
 " Test for mapping <LeftDrag> in Insert mode
 func Test_mouse_drag_insert_map()
   set mouse=a
diff --git a/src/nvim/testdir/test_search_stat.vim b/src/nvim/testdir/test_search_stat.vim
index 89e09cf85b..1822a0dce6 100644
--- a/src/nvim/testdir/test_search_stat.vim
+++ b/src/nvim/testdir/test_search_stat.vim
@@ -262,6 +262,29 @@ func Test_searchcount_fails()
   call assert_fails('echo searchcount("boo!")', 'E715:')
 endfunc
 
+func Test_search_stat_narrow_screen()
+  " This used to crash Vim
+  let save_columns = &columns
+  try
+    let after =<< trim [CODE]
+      set laststatus=2
+      set columns=16
+      set shortmess-=S showcmd
+      call setline(1, 'abc')
+      call feedkeys("/abc\<CR>:quit!\<CR>")
+      autocmd VimLeavePre * call writefile(["done"], "Xdone")
+    [CODE]
+
+    if !RunVim([], after, '--clean')
+      return
+    endif
+    call assert_equal("done", readfile("Xdone")[0])
+    call delete('Xdone')
+  finally
+    let &columns = save_columns
+  endtry
+endfunc
+
 func Test_searchcount_in_statusline()
   CheckScreendump
 
diff --git a/src/nvim/testdir/test_window_cmd.vim b/src/nvim/testdir/test_window_cmd.vim
index aebc3bf2f3..3dc9837022 100644
--- a/src/nvim/testdir/test_window_cmd.vim
+++ b/src/nvim/testdir/test_window_cmd.vim
@@ -1385,17 +1385,20 @@ func Test_win_move_separator()
   call assert_equal(w0, winwidth(0))
   call assert_true(win_move_separator(0, -1))
   call assert_equal(w0, winwidth(0))
+
   " check that win_move_separator doesn't error with offsets beyond moving
   " possibility
   call assert_true(win_move_separator(id, 5000))
   call assert_true(winwidth(id) > w)
   call assert_true(win_move_separator(id, -5000))
   call assert_true(winwidth(id) < w)
+
   " check that win_move_separator returns false for an invalid window
   wincmd =
   let w = winwidth(0)
   call assert_false(win_move_separator(-1, 1))
   call assert_equal(w, winwidth(0))
+
   " check that win_move_separator returns false for a floating window
   let id = nvim_open_win(
         \ 0, 0, #{relative: 'editor', row: 2, col: 2, width: 5, height: 3})
@@ -1403,6 +1406,13 @@ func Test_win_move_separator()
   call assert_false(win_move_separator(id, 1))
   call assert_equal(w, winwidth(id))
   call nvim_win_close(id, 1)
+
+  " check that using another tabpage fails without crash
+  let id = win_getid()
+  tabnew
+  call assert_fails('call win_move_separator(id, -1)', 'E1308:')
+  tabclose
+
   %bwipe!
 endfunc
 
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 6660bb4cc0..f0797cfa38 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -4230,6 +4230,8 @@ static int leave_tabpage(buf_T *new_curbuf, bool trigger_leave_autocmds)
       return FAIL;
     }
   }
+
+  reset_dragwin();
   tp->tp_curwin = curwin;
   tp->tp_prevwin = prevwin;
   tp->tp_firstwin = firstwin;
@@ -4292,6 +4294,10 @@ static void enter_tabpage(tabpage_T *tp, buf_T *old_curbuf, bool trigger_enter_a
     clear_cmdline = true;
   }
 
+  // If there was a click in a window, it won't be usable for a following
+  // drag.
+  reset_dragwin();
+
   // The tabpage line may have appeared or disappeared, may need to resize the frames for that.
   // When the Vim window was resized or ROWS_AVAIL changed need to update frame sizes too.
   if (curtab->tp_old_Rows_avail != ROWS_AVAIL || (old_off != firstwin->w_winrow)) {