Exception: Cannot construct a Paragraph with StyleSpans object that contains no StyleSpan objects

[JFormDesigner]

I'm getting the below exception with current master branch of RichTextFX in Markdown Writer FX, but it works fine with RichTextFX 0.8.2.

Was able to find the commit that causes the exception: PR #685
Before this PR was merged, it worked. After merging, it fails.

The exception assumes a problem on my side, but I have no idea how to fix this.

I'm having a StyleClassedTextArea and using a StyleSpansBuilder<Collection<String>> to build style spans for the whole text.

Any ideas?

Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException:
 Cannot construct a Paragraph with StyleSpans object that contains no StyleSpan objects
	at org.fxmisc.richtext.model.Paragraph.<init>(Paragraph.java:124)
	at org.fxmisc.richtext.model.Paragraph.restyle(Paragraph.java:325)
	at org.fxmisc.richtext.model.GenericEditableStyledDocumentBase.lambda$11(GenericEditableStyledDocumentBase.java:170)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument.lambda$14(ReadOnlyStyledDocument.java:366)
	at org.reactfx.util.Tuple2.map(Tuple2.java:31)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument.lambda$12(ReadOnlyStyledDocument.java:365)
	at org.reactfx.util.Tuple2.map(Tuple2.java:31)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument.replace(ReadOnlyStyledDocument.java:364)
	at org.fxmisc.richtext.model.ReadOnlyStyledDocument.replace(ReadOnlyStyledDocument.java:354)
	at org.fxmisc.richtext.model.GenericEditableStyledDocumentBase.setStyleSpans(GenericEditableStyledDocumentBase.java:164)
	at org.fxmisc.richtext.model.SimpleEditableStyledDocument.setStyleSpans(SimpleEditableStyledDocument.java:1)
	at org.fxmisc.richtext.GenericStyledArea.setStyleSpans(GenericStyledArea.java:1138)
	at org.markdownwriterfx.editor.MarkdownSyntaxHighlighter.highlight(MarkdownSyntaxHighlighter.java:278)
	at org.markdownwriterfx.editor.MarkdownSyntaxHighlighter.highlight(MarkdownSyntaxHighlighter.java:198)
	at org.markdownwriterfx.editor.MarkdownEditorPane.applyHighlighting(MarkdownEditorPane.java:299)
	at org.markdownwriterfx.editor.MarkdownEditorPane.textChanged(MarkdownEditorPane.java:273)
	at org.markdownwriterfx.editor.MarkdownEditorPane.lambda$0(MarkdownEditorPane.java:100)
	at org.reactfx.value.ChangeListenerWrapper.accept(Val.java:786)
	at org.reactfx.util.AbstractReducingStreamNotifications.lambda$head$0(NotificationAccumulator.java:248)
	at org.reactfx.ObservableBase.notifyObservers(ObservableBase.java:68)
	at org.reactfx.SuspendableBase.resume(SuspendableBase.java:64)
	at org.reactfx.CloseableOnceGuard.close(Guard.java:49)
	at org.reactfx.MultiGuard.close(Guard.java:83)
	at org.reactfx.Suspendable$1.resumeSource(Suspendable.java:118)
	at org.reactfx.Suspendable$1.suspendSource(Suspendable.java:104)
	at org.reactfx.util.NonAccumulativeStreamNotifications.lambda$head$0(NotificationAccumulator.java:134)
	at org.reactfx.ObservableBase.notifyObservers(ObservableBase.java:68)
	at org.reactfx.ObservableBase.notifyObservers(ObservableBase.java:57)
	at org.reactfx.ProperEventStream.emit(ProperEventStream.java:18)
	at org.reactfx.EventStreams$3.lambda$observeInputs$0(EventStreams.java:105)
	at org.reactfx.value.ChangeListenerWrapper.accept(Val.java:786)
	at org.reactfx.util.AbstractReducingStreamNotifications.lambda$head$0(NotificationAccumulator.java:248)
	at org.reactfx.ObservableBase.notifyObservers(ObservableBase.java:68)
	at org.reactfx.ObservableBase.notifyObservers(ObservableBase.java:57)
	at org.reactfx.value.ValBase.invalidate(ValBase.java:32)
	at org.reactfx.SuspendableBoolean.release(SuspendableBoolean.java:24)
	at org.reactfx.CloseableOnceGuard.close(Guard.java:49)
	at org.reactfx.Suspendable.suspendWhile(Suspendable.java:49)
	at org.fxmisc.richtext.model.GenericEditableStyledDocumentBase.update(GenericEditableStyledDocumentBase.java:228)
	at org.reactfx.util.Tuple3.exec(Tuple3.java:43)
	at org.fxmisc.richtext.model.GenericEditableStyledDocumentBase.replace(GenericEditableStyledDocumentBase.java:135)
	at org.fxmisc.richtext.model.SimpleEditableStyledDocument.replace(SimpleEditableStyledDocument.java:1)
	at org.fxmisc.richtext.GenericStyledArea.replace(GenericStyledArea.java:1187)
	at org.fxmisc.richtext.GenericStyledArea.replaceText(GenericStyledArea.java:1174)
	at org.fxmisc.richtext.EditActions.replaceText(EditActions.java:148)
	at org.markdownwriterfx.editor.MarkdownEditorPane.setMarkdown(MarkdownEditorPane.java:225)
	at org.markdownwriterfx.FileEditor.load(FileEditor.java:267)
	at org.markdownwriterfx.FileEditor.activated(FileEditor.java:216)
	at org.markdownwriterfx.FileEditor.lambda$5(FileEditor.java:97)
	at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
	at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
	at java.lang.Thread.run(Thread.java:748)

[JFormDesigner]

Was able to build a minimal app that reproduces the problem. Running the below app immediately throws the above exception:

import java.util.Collection;
import java.util.Collections;
import org.fxmisc.richtext.StyleClassedTextArea;
import org.fxmisc.richtext.model.StyleSpansBuilder;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class StyleSpansIssue extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        StyleClassedTextArea textArea = new StyleClassedTextArea();
        textArea.replaceText("* a\n\n");

        StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();
        spansBuilder.add(Collections.singleton("cls1"), 1);
        spansBuilder.add(Collections.singleton("cls2"), 3);
        spansBuilder.add(Collections.emptyList(), 1);
        textArea.setStyleSpans(0, spansBuilder.create());

        Scene scene = new Scene(new StackPane(textArea), 600, 400);
        primaryStage.setScene(scene);
        primaryStage.setTitle("StyleSpansIssue");
        primaryStage.show();
    }
}

[Bibek1998]

I want to make certain lines/paragraphs of codearea editablitiy false how to do it ?