If you open up the chamber GUI for a ship that has no chambers, you get a runtime exception saying you have no tree.
I know it's done on purpose but no harm in having a report about it so it's not forgotten.
java.lang.RuntimeException: No Tree: 0 at org.schema.game.client.view.gui.reactor.GUIReactorPanel.getSelectedTree(GUIReactorPanel.java:350) at org.schema.game.client.view.gui.reactor.GUIReactorPanel$4.toString(GUIReactorPanel.java:210) at org.schema.schine.graphicsengine.forms.gui.newgui.GUIHorizontalButton.init(GUIHorizontalButton.java:43) at org.schema.schine.graphicsengine.forms.gui.newgui.GUIHorizontalButton.<init>(GUIHorizontalButton.java:58) at org.schema.schine.graphicsengine.forms.gui.newgui.GUIHorizontalButtonTablePane.addButton(GUIHorizontalButtonTablePane.java:88) at org.schema.game.client.view.gui.reactor.GUIReactorPanel.createReactorSelect(GUIReactorPanel.java:203) at org.schema.game.client.view.gui.reactor.GUIReactorPanel.createTestTab(GUIReactorPanel.java:155) at org.schema.game.client.view.gui.reactor.GUIReactorPanel.onInit(GUIReactorPanel.java:122) at org.schema.game.client.view.gui.reactor.ReactorTreeDialog.<init>(ReactorTreeDialog.java:21) at org.schema.game.client.controller.manager.DebugControlManager.handleKeyEvent(DebugControlManager.java:176) at org.schema.game.client.controller.manager.GlobalGameControlManager.handleKeyEvent(GlobalGameControlManager.java:126) at org.schema.game.client.controller.GameClientController.handleKeyEvent(GameClientController.java:3467) at org.schema.schine.input.BasicInputController.updateInput(BasicInputController.java:185) at org.schema.game.client.controller.GameClientController.updateStateInput(GameClientController.java:1465) at org.schema.schine.graphicsengine.core.GLFrame.doFrameAndUpdate(GLFrame.java:673) at org.schema.schine.graphicsengine.core.GraphicsContext.mainLoop(GraphicsContext.java:808) at org.schema.schine.graphicsengine.core.GraphicsContext.startUp(GraphicsContext.java:705) at org.schema.game.client.controller.GameMainMenuController.startGraphics(GameMainMenuController.java:1148) at org.schema.game.common.Starter.startMainMenu(Starter.java:1452) at org.schema.game.common.Starter.main(Starter.java:996)