tornadofx: Textfield delete char string out of range

Hey I think this is a bug I cant get my head around this problem it happens when I just create a view with a textfield. and when I then type text into it it is all good but when i hold down the delete char key or just pressing quickly I get the following pop up error

java.lang.StringIndexOutOfBoundsException: String index out of range: 15 at java.lang.String.charAt(String.java:658) at com.sun.glass.ui.win.WinTextRangeProvider.GetBoundingRectangles(WinTextRangeProvider.java:314) 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)

I am using java 8

`<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>com.example</groupId>
<artifactId>UnitStatus</artifactId>
<version>1.0</version>
<packaging>jar</packaging>

<properties>
    <kotlin.version>1.2.51</kotlin.version>
</properties>


<dependencies>
    <dependency>
        <groupId>no.tornado</groupId>
        <artifactId>tornadofx</artifactId>
        <version>1.7.16</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-stdlib-jdk8</artifactId>
        <version>${kotlin.version}</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-test</artifactId>
        <version>${kotlin.version}</version>
        <scope>test</scope>
    </dependency>


    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.197</version>
        <scope>test</scope>
    </dependency>



    <dependency>
        <groupId>org.jetbrains.exposed</groupId>
        <artifactId>exposed</artifactId>
        <version>0.10.3</version>
        <type>pom</type>
    </dependency>

    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>3.17</version>
    </dependency>
</dependencies>

<build>
    <sourceDirectory>src/main/kotlin</sourceDirectory>
    <plugins>
        <plugin>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-plugin</artifactId>
            <version>${kotlin.version}</version>
            <executions>
                <execution>
                    <id>compile</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                    <configuration>
                    <jvmTarget>1.8</jvmTarget>
                    </configuration>
                </execution>
                <execution>
                    <id>test-compile</id>
                    <phase>test-compile</phase>
                    <goals>
                        <goal>test-compile</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <jvmTarget>1.8</jvmTarget>
            </configuration>
        </plugin>
    </plugins>
</build>

<repositories>

    <repository>
        <id>snapshots-repo</id>
        <url>https://oss.sonatype.org/content/repositories/snapshots</url>
        <releases><enabled>false</enabled></releases>
        <snapshots><enabled>true</enabled></snapshots>
    </repository>
</repositories>

</project>`