Creating multiple new child forms from a single form
Your code is very small for a good review, but a few things can be mentioned:

1) naming - it is better to name your variables by what they represent. E.g. DemoTabContentMiniGraph1, 2, 3 should can be named something like MiniGraphFS1View, MiniGraphPs1Ps2View etc.

Also, F_CWndw_GraphFS1 can be adjusted to Pascal/Camel notation used in C# (they look to have C++ naming style)

2) passing parameters to instances - providing many parameters to a constructor works, but it may render maintainability problems in the future:


it is very hard to know what the third false in F_CWndw_GraphFS1(true, false, false, false, 0.5, 100, 0.5, 10, "Time (s)", 20, 100, 100, "Flow Rate (l/s)", 2, true, "DEMO"); means
if a new parameter must be added to the graphic, you may have to change in multiple places (constructor prototype, callers have to provide the new parameter, if it does not have a default value).


A better way is to define a class named GraphOptions or similar to encapsulate your options:

class GraphOptions
{
   float MinValue { get; set; }
   float MaxValue { get; set; }
   String XLabel { get; set; }
   // other properties come here

   // you can also define a constructor to assign default values
}


Your construction code will look something like this (much longer, but much easier to understand):

var FormMiniGraph1 = new F_CWndw_GraphFS1(new GraphOptions() 
   { 
      Prop1 = true, 
      Prop2 = false, 
      Prop3 = false, 
      MinValue = 0.5,
      MaxValue = 100, 
      XLabel = "Time (s)"

      // all other properties remain to their default value or their value does not matter for current graph
   }


3) (possible) AddRange optimization:

If Children implements IEnumerable, AddRange can be used

Grid_miniGraph1.Children.Add(DemoTabContentMiniGraph1);
Grid_miniGraph2.Children.Add(DemoTabContentMiniGraph2);
Grid_miniGraph3.Children.Add(DemoTabContentMiniGraph3);


becomes

Grid_miniGraph1.Children.AddRange(new List&lt;WindowsFormsHost&gt;() { DemoTabContentMiniGraph1, DemoTabContentMiniGraph2, DemoTabContentMiniGraph3 };


Other aspect is the harcoded number of possible graphs. Are they so different that they must be defined one by one? Do they share common functionality?