[LyX/master] GuiGraphics: disable "Read from file" button if the values do not differ

[Juergen Spitzmueller]

commit 64a60c72eae22fcd046d96a3d62a0dcb195c61c0
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Fri Dec 31 14:32:59 2021 +0100

    GuiGraphics: disable "Read from file" button if the values do not differ
---
 src/frontends/qt/GuiGraphics.cpp |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/frontends/qt/GuiGraphics.cpp b/src/frontends/qt/GuiGraphics.cpp
index fd4e8f5..64fa397 100644
--- a/src/frontends/qt/GuiGraphics.cpp
+++ b/src/frontends/qt/GuiGraphics.cpp
@@ -337,6 +337,7 @@ void GuiGraphics::on_newGroupPB_clicked()
 void GuiGraphics::changeBB()
 {
 	bbChanged = isChangedBB();
+	getPB->setEnabled(bbChanged);
 	LYXERR(Debug::GRAPHICS, "[bb_Changed set to " << bbChanged << "]");
 	changed();
 }