kcm/rules: Improve "Ignore Geometry" property UI

This property is not used on Wayland because windows are
already not allowed to set their own geometry, so let's
hide it from the UI.

Also update the tooltip to explicitly state which properties
the `Ignore Geometry` property does affect on X11

BUG: 431265
FIXED-IN: 6.0

src/kcms/rules/rulesmodel.cpp

@@ -268,6 +268,10 @@ bool RulesModel::wmclassWarning() const
 
 bool RulesModel::geometryWarning() const
 {
+    if (!KWindowSystem::isPlatformX11()) {
+        return false;
+    }
+
     const bool ignoregeometry = m_rules["ignoregeometry"]->isEnabled()
         && m_rules["ignoregeometry"]->policy() == Rules::Force
         && m_rules["ignoregeometry"]->value() == true;
@@ -520,15 +524,20 @@ void RulesModel::populateRuleList()
     placement->setOptionsData(placementModelData());
     placement->setFlag(RuleItem::AffectsWarning);
 
-    auto ignoregeometry = addRule(new RuleItem(QLatin1String("ignoregeometry"),
-                                               RulePolicy::SetRule, RuleItem::Boolean,
-                                               i18n("Ignore requested geometry"), i18n("Size & Position"),
-                                               QIcon::fromTheme("view-time-schedule-baselined-remove"),
-                                               i18n("Windows can ask to appear in a certain position. "
-                                                    "By default this overrides the placement strategy "
-                                                    "what might be nasty if the client abuses the feature "
-                                                    "to unconditionally popup in the middle of your screen.")));
-    ignoregeometry->setFlag(RuleItem::AffectsWarning);
+    if (KWindowSystem::isPlatformX11()) {
+        // On Wayland windows cannot set their own geometry
+        auto ignoregeometry = addRule(new RuleItem(QLatin1String("ignoregeometry"),
+                                                   RulePolicy::SetRule, RuleItem::Boolean,
+                                                   i18n("Ignore requested geometry"), i18n("Size & Position"),
+                                                   QIcon::fromTheme("view-time-schedule-baselined-remove"),
+                                                   xi18nc("@info:tooltip",
+                                                          "Some applications can set their own geometry, overriding the window manager preferences. "
+                                                          "Setting this property overrides their placement requests.<nl/>"
+                                                          "This affects <interface>Size</interface> and <interface>Position</interface> "
+                                                          "but not <interface>Maximized</interface> or <interface>Fullscreen</interface> states.<nl/>"
+                                                          "Note that the position can also be used to map to a different <interface>Screen</interface>")));
+        ignoregeometry->setFlag(RuleItem::AffectsWarning);
+    }
 
     addRule(new RuleItem(QLatin1String("minsize"),
                          RulePolicy::ForceRule, RuleItem::Size,