Imageglass: Fails to start when ThumbnailBarWidth is close or greater than WindowsBound

[Otiel]

System information:

• Windows OS version: Win10 1809
• ImageGlass version: 6.0.12.29

To Reproduce

To get a clean config file:

1. Delete _igconfig.xml_ for a clean startup.
2. Start ImageGlass.
3. Perform the 4 steps of the first launch configuration.
4. Close ImageGlass.

Now to reproduce:

1. Edit _igconfig.xml_ and change:

```
<Item key="IsShowThumbnail" value="True" />
<Item key="IsThumbnailHorizontal" value="False" />
<Item key="ThumbnailBarWidth" value="990" />
```

The idea is to set `ThumbnailBarWidth` to a value close or greater than the window width defined in `frmMain.WindowsBound`. In my case, it was set to 1000 by default:

```
<Item key="frmMain.WindowsBound" value="280,125,1000,800" />
```

1. Start ImageGlass.

Actual behavior:

ImageGlass fails to start. No error is displayed.

Expected behavior:

ThumbnailBarWidth should be reset to an appropriate value and ImageGlass should start.

Screenshots:

Additional context:

It happened to me in the first place without tampering the config file. I'm not sure how though...

[fire-eggs]

Yup, I've struggled with this in the past. I thought I fixed 'em all but apparently missed something.

[fire-eggs]

Fix available in latest ImageGlass Moon. (https://imageglass.org/moon)