Hi
So what you do is something like this.
In the Screen OnVisible (and you could use a context variable im being lazy)
Set(_LeftContainerWidth, 200);
This would be the start of the width of that container, assuming you know what it is, either hard code it or make is an Environment Variable or something else.
Put it in the Width property of your Container on the left.
Then when someone clicks +
Set(_LeftContainerWidth, 0);
Now its closed
then in your other container change the X property to be
If(_LeftContainerWidth = 0, 0, _LeftContainerWidth + 5) // so it will either have its X be 0 or X = Width of Left Container + 5
Then in the Width for your right container
If(_LeftContainerWidth = 0, Parent.Width, ItsNormalWidth);
Now for the controls IN the container do the same thing for X and Width
If(_LeftContainerWidth = 0, Parent.Width, ItsNormalWidth);
If(_LeftContainerWidth = 0, 0, _LeftContainerWidth + 5) // and change the 5 to whatever you want for that control
in their widths.
and Parent.Width, may need to be Template.Width or Screen depending on how you have it.
Now since you said when they click + there must be a Save/Update button
So, click that and then do
Set(_LeftContainerWidth, 200) and bingo it all resets.