--User changes

-Give tabs a height of 4px in the qss files. Looks a little large on 4k screens, but just right on HD screens which are much more common.
 -Allow for styling of zero and non-zero variation tree nodes via qss.
 -Allow for toggling whether to interpolate between colors in the palette editor, or to do hard cuts between colors.
 -Allow for adjusting spinner values with the + = or up arrow keys to increase, and - _ or down arrow keys to decrease.
 -Allow for responding to global presses of + = and - _ to cycle up or down to specify which xform is set as the current one.
 -Allow for adding "layers" via xaos which will add a user-specified number of xforms, and set certain xaos values to 0 or 1.
 -Add a new menu item under the Edit menu to copy the OpenCL iteration kernel source to the clipboard.
 -Show text on the status bar which indicates that an OpenCL kernel compilation is taking place.
 -Show xform name on xform combo box when expanded. Adjust size to fit all names.
 -Draw post affine circles using dashed lines.
 -Prevent QSS dialog from styling its editor, which makes it easier to see text when creating styles which have custom colors for text boxes.

--Bug fixes
 -Fix up some table layouts which seemed to have regressed/decayed over time for reasons unknown.
 -Using undo/redo would create a new flame in the library every time.
 -Solo was not being preserved when using undo/redo.

--Code changes
 -Make the solo flag be a part of the flame data now.
 -Fix some tabification in the OpenCL code for EllipticVariation.
 -Fix tabification in the varState code for OpenCL.
 -Add an event called m_CompileBegun to RendererCL that is called right before an OpenCL compile is begun.
 --This required making RendererCLBase not a pure virtual base class. Member functions just return defaults.
 -Filter key presses on main window to only process the third one. This is due to Qt triggering three events for every key press.
 -The palette preview table was installing an event filter for seemingly no reason. Remove it.
 -Mark certain virtual functions as override in SpinBox and DoubleSpinBox.

Source/EmberCL/RendererCL.cpp

@@ -33,6 +33,7 @@ RendererCL<T, bucketT>::RendererCL(const vector<pair<size_t, size_t>>& devices,
 	m_PaletteFormat.image_channel_data_type = CL_FLOAT;
 	m_FinalFormat.image_channel_order = CL_RGBA;
 	m_FinalFormat.image_channel_data_type = CL_FLOAT;
+	m_CompileBegun = [&]() { };
 	Init(devices, shared, outputTexID);
 }
 
@@ -903,6 +904,7 @@ bool RendererCL<T, bucketT>::BuildIterProgramForEmber(bool doAccum)
 
 	if (b)
 	{
+		m_CompileBegun();
 		m_IterKernel = m_IterOpenCLKernelCreator.CreateIterKernelString(m_Ember, m_Params.first, m_GlobalShared.first, m_LockAccum, doAccum);
 		//cout << "Building: " << "\n" << iterProgram << "\n";
 		vector<std::thread> threads;

Source/EmberCL/RendererCL.h

@@ -19,9 +19,10 @@ class EMBERCL_API RendererCLBase
 {
 public:
 	virtual ~RendererCLBase() { }
-	virtual bool ReadFinal(v4F* pixels) = 0;
-	virtual bool ClearFinal() = 0;
-	virtual bool AnyNvidia() const = 0;
+	virtual bool ReadFinal(v4F* pixels) { return false; }
+	virtual bool ClearFinal() { return false; }
+	virtual bool AnyNvidia() const { return false; }
+	std::function<void(void)> m_CompileBegun;
 };
 
 /// <summary>