BUG: Variables calculations overwritten

[slspencer]

• Describe the bug

In the Variables Table, a Variable's calculated value can be overwritten from a formula farther down in the Variables table. The updated calculated value is then used to draw the pattern.
The Variables Table should not allow backward updates, this creates recursion. I can provide example of this, but the base problem is ability to update variables that are defined earlier in the table.

In this example, the variable is overwritten directly with a constant, even though the formula wasn't overwritten.