TilelessMap apps crash when i click on many time on Layers button

Expected behavior

according to knowledge when i click on the layers button show the layers and application should no be crash

Actual behavior

after open the application when i chose file map and click on start button after open the map when i many click on the layers button apps is crash you can see in bug video

How to reproduce

• download and open the application
• download norge.tileless map from the site mention in application
• click on choose file and select the norge.tileless
• click on start button
• for show the layers many click on layers button
• note the bug
• Browser: TilelessMap Version 0.1.5 (4) - Added on 2018-03-15
• Operating system: android version 4.4.2
• smart phone GALAXY Note 3

Recording Of The Bug