The default values on my Monoprice Ultimate are way different to what Cura has the Wanhao Duplicator 6 as. I'm guessing that Monoprice have changed these (if not, then maybe the Duplicator 6 file is wrong?). Without this profile, I had a 4hr print estimate for a piece that's only 55% through after 4hours. With this profile, it estimates 7:22 (which seems very accurate).
I got the default values from the printer when I connected Octoprint to it:
```
21:20:56: Attempting to connect to printer
21:20:56: Connection opened
< 21:20:57: start
> 21:20:57: N1 M110 *2
< 21:20:57: echo:Marlin 1.0.0
> 21:20:57: N2 M110 *1
< 21:20:57: echo: Last Updated: Jun 26 2016 12:14:19 | Author: Version DEV 3.01
> 21:20:57: N3 M115 *5
< 21:20:57: Compiled: Jun 26 2016
< 21:20:57: echo: Free Memory: 1961 PlannerBufferBytes: 1232
< 21:20:57: echo:Stored settings retrieved
< 21:20:57: echo:Steps per unit:
< 21:20:57: echo: M92 X80.04 Y80.04 Z400.48 E94.30
< 21:20:57: echo:Maximum feedrates (mm/s):
< 21:20:57: echo: M203 X300.00 Y300.00 Z5.00 E25.00
< 21:20:57: echo:Maximum Acceleration (mm/s2):
< 21:20:57: echo: M201 X3000 Y3000 Z100 E500
< 21:20:57: echo:Acceleration: S=acceleration, T=retract acceleration
< 21:20:57: echo: M204 S800.00 T800.00
< 21:20:57: echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
< 21:20:57: echo: M205 S0.00 T0.00 B20000 X10.00 Z0.40 E1.00
< 21:20:57: echo:Home offset (mm):
< 21:20:57: echo: M206 X0.00 Y0.00 Z0.40
```
This padding made it break the height of the item for some reason. I guess that is a Qt bug.
In any case, the padding shouldn't be there either since the lining is on the inside of the child buttons so the padding only causes a gap to appear on the left and right sides, which looks weird.
Contributes to issue CURA-6029.
Edit: Originally this was more or less the same fix as what Diego just did at the same time, which caused a merge conflict, but I think my solution is more elegant than the ternary operator that was originally there so I'm keeping mine.
This way there is a little bit more space for the text 'No time estimation available', which was previously abbreviated to 'No time estimation availa...'.
CURA-6015
ListModels should not modify items directly. All ListModels should use
setItems() and the insertions/removals/modifications will be done in
setItems() itself.