tdf#99701 Calc multiline input: Give button a fixed width

It should not depend on the scrollbar size as the scrollbar
is very thin in some environments (esp. GTK3)

Change-Id: I5cb4b145c21614482d7d402cebc33600f29cce09
Reviewed-on: https://gerrit.libreoffice.org/24688Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>

sc/source/ui/app/inputwin.cxx

@@ -72,6 +72,7 @@
 
 #define THESIZE             1000000 // Should be more than enough!
 #define TBX_WINDOW_HEIGHT   22 // in pixel - TODO: The same on all systems?
+#define MULTILINE_BUTTON_WIDTH 20 // Width of the button which opens the multiline dropdown
 #define LEFT_OFFSET         5
 #define INPUTWIN_MULTILINES 6
 const long BUTTON_OFFSET = 2; ///< space between input line and the button to expand / collapse
@@ -882,7 +883,7 @@ ScInputBarGroup::ScInputBarGroup(vcl::Window* pParent, ScTabViewShell* pViewSh)
     maTextWnd->SetQuickHelpText(ScResId(SCSTR_QHELP_INPUTWND));
     maTextWnd->SetHelpId(HID_INSWIN_INPUT);
 
-    Size aSize(GetSettings().GetStyleSettings().GetScrollBarSize(), maTextWnd->GetPixelHeightForLines(1));
+    Size aSize(MULTILINE_BUTTON_WIDTH, maTextWnd->GetPixelHeightForLines(1));
 
     maButton->SetClickHdl(LINK(this, ScInputBarGroup, ClickHdl));
     maButton->SetSizePixel(aSize);