Should I really call something the "empty box" problem?

__main__.py

@@ -128,7 +128,10 @@ class MainUI(QtWidgets.QMainWindow, mainwindow.Ui_MainWindow):
         # The rest is illustrated using informative variable names
         space_occupied = num_images * default_size
         space_left = (
-            self.listView.viewport().width() - space_occupied - 19)  # 19 is the scrollbar width
+            self.listView.viewport().width() - space_occupied - 19)  # 12 is the scrollbar width
+                                                                     # Larger numbers keep reduce
+                                                                     # flickering but also increase
+                                                                     # the distance from the scrollbar
         try:
             layout_extra_space_per_image = space_left // num_images
             self.listView.setGridSize(

mainwindow.py

@@ -2,7 +2,7 @@
 
 # Form implementation generated from reading ui file 'resources/main.ui'
 #
-# Created by: PyQt5 UI code generator 5.9
+# Created by: PyQt5 UI code generator 5.9.1
 #
 # WARNING! All changes made in this file will be lost!
 
@@ -33,8 +33,9 @@ class Ui_MainWindow(object):
         self.listView.setProperty("showDropIndicator", False)
         self.listView.setSelectionMode(QtWidgets.QAbstractItemView.ExtendedSelection)
         self.listView.setMovement(QtWidgets.QListView.Static)
-        self.listView.setResizeMode(QtWidgets.QListView.Adjust)
-        self.listView.setLayoutMode(QtWidgets.QListView.Batched)
+        self.listView.setProperty("isWrapping", True)
+        self.listView.setResizeMode(QtWidgets.QListView.Fixed)
+        self.listView.setLayoutMode(QtWidgets.QListView.SinglePass)
         self.listView.setViewMode(QtWidgets.QListView.IconMode)
         self.listView.setUniformItemSizes(True)
         self.listView.setWordWrap(True)

resources/main.ui

@@ -49,11 +49,14 @@
               <property name="movement">
                <enum>QListView::Static</enum>
               </property>
+              <property name="isWrapping" stdset="0">
+               <bool>true</bool>
+              </property>
               <property name="resizeMode">
-               <enum>QListView::Adjust</enum>
+               <enum>QListView::Fixed</enum>
               </property>
               <property name="layoutMode">
-               <enum>QListView::Batched</enum>
+               <enum>QListView::SinglePass</enum>
               </property>
               <property name="spacing">
                <number>0</number>