[LyX/master] Fix setting of math matrix size with mouse

[Yuriy Skalko]

commit 110862b09f538bd7412f9e747641a8ae14f3f70a
Author: Yuriy Skalko <yuriy.skalko at gmail.com>
Date:   Thu Feb 18 15:36:24 2021 +0200

    Fix setting of math matrix size with mouse
---
 src/frontends/qt/EmptyTable.cpp |   16 ++++++++++++----
 src/frontends/qt/EmptyTable.h   |    4 ++++
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/frontends/qt/EmptyTable.cpp b/src/frontends/qt/EmptyTable.cpp
index bc2963b..80cbe88 100644
--- a/src/frontends/qt/EmptyTable.cpp
+++ b/src/frontends/qt/EmptyTable.cpp
@@ -22,10 +22,6 @@
  * A simple widget for a quick "preview" in TabularCreateDialog
  */
 
-unsigned int const cellheight = 20;
-unsigned int const cellwidth = 30;
-
-
 EmptyTable::EmptyTable(QWidget * parent, int rows, int columns)
 	: QTableWidget(rows, columns, parent)
 {
@@ -34,7 +30,9 @@ EmptyTable::EmptyTable(QWidget * parent, int rows, int columns)
 	setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
 	viewport()->resize(cellheight * rows, cellwidth * columns);
 	setSelectionMode(QAbstractItemView::NoSelection);
+	setFocusPolicy(Qt::NoFocus);
 	setEditTriggers(QAbstractItemView::NoEditTriggers);
+	adjustMinCellSize();
 }
 
 
@@ -43,6 +41,16 @@ QSize EmptyTable::sizeHint() const
 	return QSize(cellwidth * (2 + columnCount()), cellheight * (2 + rowCount()));
 }
 
+
+void EmptyTable::adjustMinCellSize()
+{
+	setRowHeight(0, cellheight);
+	cellheight = rowHeight(0);
+	setColumnWidth(0, cellwidth);
+	cellwidth = columnWidth(0);
+}
+
+
 void EmptyTable::resetCellSize()
 {
 	for(int i = 0; i < rowCount(); ++i)
diff --git a/src/frontends/qt/EmptyTable.h b/src/frontends/qt/EmptyTable.h
index 9926526..9285db5 100644
--- a/src/frontends/qt/EmptyTable.h
+++ b/src/frontends/qt/EmptyTable.h
@@ -49,6 +49,10 @@ protected:
 	virtual void resetCellSize();
 
 private:
+	void adjustMinCellSize();
+
+	int cellheight = 20;
+	int cellwidth = 30;
 };