diff --git a/src/appearancegtk3.cpp b/src/appearancegtk3.cpp
--- a/src/appearancegtk3.cpp
+++ b/src/appearancegtk3.cpp
@@ -40,11 +40,12 @@
 
     //we just want actual themes
     QStringList themes;
-    for(QFileInfoList::iterator it=availableThemes.begin(); it!=availableThemes.end(); ++it) {
-        bool hasGtkrc = QDir(it->filePath()).exists("gtk-3.0");
 
-        //If it doesn't exist, we don't want it on the list
-        if(hasGtkrc)
+    // Check that the theme contains a gtk-3.* subdirectory
+    QStringList gtk3SubdirPattern{QStringLiteral("gtk-3.*")};
+    for(QFileInfoList::const_iterator it=availableThemes.constBegin(); it!=availableThemes.constEnd(); ++it) {
+        QDir themeDir(it->filePath());
+        if(!themeDir.entryList(gtk3SubdirPattern, QDir::Dirs).isEmpty())
             themes += it->filePath();
     }
 
diff --git a/src/ui/gui.ui b/src/ui/gui.ui
--- a/src/ui/gui.ui
+++ b/src/ui/gui.ui
@@ -191,12 +191,6 @@
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
-     <property name="minimumSize">
-      <size>
-       <width>0</width>
-       <height>100</height>
-      </size>
-     </property>
      <property name="maximumSize">
       <size>
        <width>16777215</width>