Better support for dark theme

src/traceAnalyzer/presentation/tracePlotMouseLabel.h

@@ -63,6 +63,7 @@ public:
         clkPeriod(clkPeriod),
         timeDifferenceSpan(timeDifferenceSpan)
     {
+        setTrackerPen(traceplot->palette().text().color());
     }
 
     void setMode(MouseLabelMode mode);

src/traceAnalyzer/presentation/traceplot.cpp

@@ -382,6 +382,8 @@ void TracePlot::setUpGrid()
 {
     unsigned int clk = navigator->GeneralTraceInfo().clkPeriod;
     QwtPlotGrid* grid = new ClkGrid(clk, GridVisiblityClks * clk);
+    grid->setMajorPen(palette().text().color(), 1.0);
+    grid->setMinorPen(palette().text().color(), 1.0);
     grid->setZ(0);
     grid->attach(this);
 }