[polari] roomStack: Only consider mapped widgets for entry-area-height

[Marge Bot <marge-bot src gnome org>]

commit d36654b569b89c619a34070483b747f4fb22a326
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Sep 3 20:54:22 2021 +0200

    roomStack: Only consider mapped widgets for entry-area-height
    
    Size groups no longer force an allocation on unmapped widgets, so
    those will report a size of 0 (which is obviously not what we want).
    
    Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/229>

 src/roomStack.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/roomStack.js b/src/roomStack.js
index 43eebdba..5c150bc1 100644
--- a/src/roomStack.js
+++ b/src/roomStack.js
@@ -63,8 +63,10 @@ export default GObject.registerClass({
     vfunc_size_allocate(allocation) {
         super.vfunc_size_allocate(allocation);
 
-        const [firstEntry] = this._sizeGroup.get_widgets();
-        const entryHeight = firstEntry.get_allocated_height() - 1;
+        const [firstEntry] =
+            this._sizeGroup.get_widgets().filter(w => w.get_mapped());
+        const entryHeight = firstEntry
+            ? firstEntry.get_allocated_height() - 1 : 0;
         if (this._entryAreaHeight !== entryHeight) {
             this._entryAreaHeight = entryHeight;
             this.notify('entry-area-height');