IDEA-345661 Don't associate removed plugin UI theme with the Default editor scheme after unloading the plugin

GitOrigin-RevId: 20993500abda9a4247e9180fc49a20b5f9c08fe8

platform/editor-ui-api/src/com/intellij/openapi/editor/colors/EditorColorsManager.java

@@ -35,6 +35,8 @@ public abstract class EditorColorsManager {
 
   public abstract @NotNull EditorColorsScheme getGlobalScheme();
 
+  public abstract @Nullable EditorColorsScheme getActiveVisibleScheme();
+
   public abstract EditorColorsScheme getScheme(@NotNull String schemeName);
 
   public abstract boolean isDefaultScheme(EditorColorsScheme scheme);

platform/platform-impl/src/com/intellij/ide/ui/laf/LafManagerImpl.kt

@@ -527,7 +527,9 @@ class LafManagerImpl(private val coroutineScope: CoroutineScope) : LafManager(),
   private fun setLookAndFeelImpl(lookAndFeelInfo: UIThemeLookAndFeelInfo, installEditorScheme: Boolean) {
     val oldLaf = currentTheme
 
-    rememberSchemeForLaf(EditorColorsManager.getInstance().globalScheme)
+    EditorColorsManager.getInstance().activeVisibleScheme ?.let {
+      rememberSchemeForLaf(it)
+    }
 
     if (oldLaf !== lookAndFeelInfo && oldLaf != null) {
       oldLaf.dispose()

platform/platform-impl/src/com/intellij/openapi/editor/colors/impl/EditorColorsManagerImpl.kt

@@ -374,12 +374,14 @@ class EditorColorsManagerImpl @NonInjectable constructor(schemeManagerFactory: S
     }.getOrLogException(LOG)
   }
 
-  override fun getGlobalScheme(): EditorColorsScheme {
+  override fun getGlobalScheme(): EditorColorsScheme = activeVisibleScheme ?: getDefaultScheme()
+
+  override fun getActiveVisibleScheme(): EditorColorsScheme? {
     val scheme = schemeManager.activeScheme
     if (scheme is AbstractColorsScheme && !scheme.isReadOnly && !scheme.isVisible) {
-      return getDefaultScheme()
+      return null
     }
-    return scheme?.let { getEditableCopy(it) } ?: scheme ?: getDefaultScheme()
+    return scheme?.let { getEditableCopy(it) } ?: scheme
   }
 
   private fun getDefaultScheme(): EditorColorsScheme {