Gui: fix several regressions in DlgSettingsColorGradientImp

* make line edit fields wide enough to not truncate the text
* fix error: Unhandled Base::Exception caught in GUIApplication::notify.

src/Gui/DlgSettingsColorGradientImp.cpp

@@ -24,6 +24,7 @@
 #ifndef _PreComp_
 # include <cmath>
 # include <QDoubleValidator>
+# include <QFontMetrics>
 # include <QLocale>
 # include <QMessageBox>
 #endif
@@ -31,6 +32,7 @@
 #include "DlgSettingsColorGradientImp.h"
 #include "ui_DlgSettingsColorGradient.h"
 #include "SpinBox.h"
+#include "Tools.h"
 
 
 using namespace Gui::Dialog;
@@ -50,6 +52,9 @@ DlgSettingsColorGradientImp::DlgSettingsColorGradientImp( QWidget* parent, Qt::W
     ui->floatLineEditMax->setValidator(fMaxVal);
     fMinVal = new QDoubleValidator(-1000,1000,ui->spinBoxDecimals->maximum(),this);
     ui->floatLineEditMin->setValidator(fMinVal);
+
+    QFontMetrics fm(ui->floatLineEditMax->font());
+    ui->floatLineEditMax->setMinimumWidth(QtTools::horizontalAdvance(fm, QString::fromLatin1("-1000.000000")));
 }
 
 /**
@@ -157,7 +162,7 @@ void DlgSettingsColorGradientImp::accept()
     double fMax = QLocale().toDouble(ui->floatLineEditMax->text());
     double fMin = QLocale().toDouble(ui->floatLineEditMin->text());
 
-    if (fMax < fMin) {
+    if (fMax <= fMin) {
         QMessageBox::warning(this, tr("Wrong parameter"),
             tr("The maximum value must be higher than the minimum value."));
     }

src/Gui/SoFCColorBar.cpp

@@ -199,7 +199,13 @@ float SoFCColorBar::getMaxValue () const
 
 bool SoFCColorBar::customize()
 {
-    return this->getActiveBar()->customize();
+    try {
+        return this->getActiveBar()->customize();
+    }
+    catch (const Base::ValueError& e) {
+        e.ReportException();
+        return false;
+    }
 }
 
 App::Color SoFCColorBar::getColor( float fVal ) const