4 files changed, 18 insertions, 1 deletions
diff --git a/src/nvim/highlight.c b/src/nvim/highlight.c
index 4c5fca6d39..3ba02be32d 100644
--- a/src/nvim/highlight.c
+++ b/src/nvim/highlight.c
@@ -160,14 +160,19 @@ void update_window_hl(win_T *wp, bool invalid)
   wp->w_hl_needs_update = false;
 
   // determine window specific background set in 'winhighlight'
+  bool float_win = wp->w_floating && !wp->w_float_config.external;
   if (wp != curwin && wp->w_hl_ids[HLF_INACTIVE] > 0) {
     wp->w_hl_attr_normal = hl_get_ui_attr(HLF_INACTIVE,
                                           wp->w_hl_ids[HLF_INACTIVE], true);
+  } else if (float_win && wp->w_hl_ids[HLF_NFLOAT] > 0) {
+    wp->w_hl_attr_normal = hl_get_ui_attr(HLF_NFLOAT,
+                                          wp->w_hl_ids[HLF_NFLOAT], true);
   } else if (wp->w_hl_id_normal > 0) {
     wp->w_hl_attr_normal = hl_get_ui_attr(-1, wp->w_hl_id_normal, true);
   } else {
-    wp->w_hl_attr_normal = 0;
+    wp->w_hl_attr_normal = float_win ? HL_ATTR(HLF_NFLOAT) : 0;
   }
+
   if (wp != curwin) {
     wp->w_hl_attr_normal = hl_combine_attr(HL_ATTR(HLF_INACTIVE),
                                            wp->w_hl_attr_normal);
diff --git a/src/nvim/highlight_defs.h b/src/nvim/highlight_defs.h
index 1da33bfea5..746d2c2dfc 100644
--- a/src/nvim/highlight_defs.h
+++ b/src/nvim/highlight_defs.h
@@ -90,6 +90,7 @@ typedef enum {
   , HLF_0           // Whitespace
   , HLF_INACTIVE    // NormalNC: Normal text in non-current windows
   , HLF_MSGSEP      // message separator line
+  , HLF_NFLOAT      // Floating window
   , HLF_COUNT       // MUST be the last one
 } hlf_T;
 
@@ -142,6 +143,7 @@ EXTERN const char *hlf_names[] INIT(= {
   [HLF_0] = "Whitespace",
   [HLF_INACTIVE] = "NormalNC",
   [HLF_MSGSEP] = "MsgSeparator",
+  [HLF_NFLOAT] = "NormalFloat",
 });
 
 
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 0104f0d834..8c3ce823d3 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -5956,6 +5956,7 @@ static const char *highlight_init_both[] = {
   "default link Substitute Search",
   "default link Whitespace NonText",
   "default link MsgSeparator StatusLine",
+  "default link NormalFloat Pmenu",
   NULL
 };
 
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 25e6bfc565..edb5b06a2e 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -567,6 +567,10 @@ win_T *win_new_float(win_T *wp, int width, int height, FloatConfig config,
   wp->w_floating = 1;
   wp->w_status_height = 0;
   wp->w_vsep_width = 0;
+
+  // TODO(bfredl): use set_option_to() after merging #9110 ?
+  wp->w_p_nu = false;
+  wp->w_allbuf_opt.wo_nu = false;
   win_config_float(wp, width, height, config);
   wp->w_pos_changed = true;
   redraw_win_later(wp, VALID);
@@ -586,6 +590,7 @@ void win_config_float(win_T *wp, int width, int height,
     config.window = curwin->handle;
   }
 
+  bool change_external = config.external != wp->w_float_config.external;
   wp->w_float_config = config;
 
   if (!ui_has(kUIMultigrid)) {
@@ -596,6 +601,10 @@ void win_config_float(win_T *wp, int width, int height,
   win_set_inner_size(wp);
   must_redraw = MAX(must_redraw, VALID);
   wp->w_pos_changed = true;
+  if (change_external) {
+    wp->w_hl_needs_update = true;
+    redraw_win_later(wp, NOT_VALID);
+  }
 }
 
 static void ui_ext_win_position(win_T *wp)