Uncaught AssertionError: The expression evaluated to a falsy value: (0, _assert.default)(dockP...

[Enter steps to reproduce:]

1. ...
2. ...

**Atom**: 1.55.0 x64
**Electron**: 6.1.12
**OS**: Unknown Windows version
**Thrown From**: [atom-ide-debugger](https://github.com/atom-ide-community/atom-ide-debugger) package 0.0.3

### Stack Trace

Uncaught AssertionError: The expression evaluated to a falsy value:

(0, _assert.default)(dockPane.element != null)

```
At assert.js:362

AssertionError [ERR_ASSERTION] [ERR_ASSERTION]: The expression evaluated to a falsy value:

(0, _assert.default)(dockPane.element != null)

at DebuggerLayoutManager._overridePaneInitialHeight (/packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:113:25)
at Object.onPaneResize (/packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:149:14)
at /packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:354:24
at Function.simpleDispatch (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:1190181)
at Emitter.emit (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:1191622)
at Pane.setFlexScale (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:454850)
at Pane.split (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:466051)
at Pane.splitDown (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:465756)
at DebuggerLayoutManager._appendItemToDock (/packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:325:20)
at /packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:632:14
at Array.forEach ()
at DebuggerLayoutManager.showDebuggerViews (/packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:606:181)
at DebuggerLayoutManager.showHiddenDebuggerPane (/packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:238:10)
at /packages/atom-ide-debugger/dist/ui/DebuggerLayoutManager.js:88:39)
at CommandRegistry.handleCommandEvent (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:350382)
at Object.didConfirmSelection (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:684525)
at SelectListView.confirmSelection (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:856521)
at SelectListView.didClickItem (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:854463)
at ListItemView.onclick (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:853453)
at ListItemView.didClick (~/AppData/Local/atom/app-1.55.0/resources/app/static/:11:857541)
```

### Commands

```
-2:59.1.0 debugger:toggle-breakpoint (div.highlights)
-2:49.2.0 pane:split-up-and-copy-active-item (div#linter-panel.)
-2:47 pane:split-down-and-copy-active-item (div.item-views)
-2:44.9.0 pane:split-up-and-copy-active-item (div#linter-panel.)
3x -2:34.4.0 pane:close (div.item-views)
-2:13.4.0 command-palette:toggle (input.hidden-input)
2x -2:08.8.0 core:move-down (input.hidden-input)
-2:07.2.0 core:confirm (input.hidden-input)
-2:07.2.0 debugger:run-to-location (input.hidden-input)
4x -1:55.8.0 debugger:toggle-breakpoint (div.highlights)
-1:45.6.0 command-palette:toggle (input.hidden-input)
-1:40.2.0 core:backspace (input.hidden-input)
-1:35.4.0 debugger:show-window-Debugger (input.hidden-input)
```

### Non-Core Packages

```
atom-ide-base 2.3.5
atom-ide-console 0.0.2
atom-ide-datatip 0.24.0
atom-ide-debugger 0.0.3
atom-ide-definitions 0.4.1
atom-ide-hyperclick 1.0.9
atom-ide-markdown-service 2.0.0
atom-ide-outline 2.0.0
atom-ide-signature-help 0.15.3
atom-material-syntax 1.0.8
busy-signal 2.0.1
ide-python 1.7.4
linter 3.3.0
linter-ui-default 3.3.0
run 0.0.1
teletype 0.13.4
```