Log Message:
Hot off the press, update to QCAD 3.16.6, with ChangeLog:

3.16.6 (2017/03/17)

    Edit > Application / Drawing Preferences:
        Dimensions:
            Add preference to use comma instead of point as decimal separator
    QCAD Professional:
        Command line tools:
            dwg2dwg:
                Add switch for font substitution (-t FONT1:FONT2)
    Platforms:
        Linux:
            Fix keyboard input (add plugin directory \ 
"platforminputcontexts")
            64bit: Update to Qt 5.8.0
                fix file dialog crash on some systems
    Draw > Shape:
        Add option to add solid fill for shape (rectangle or polygon)
    Modify > Edit Text:
        Focus on text input field when editing simple texts
        Add shortcut to confirm text dialog: Ctrl-Enter (Cmd-Enter)
    Misc > Draw > Dovetail from 2 Points:
        Draw dovetail joins between two given points
    Bug fixes:
        FS#1543 - Input with dead-keys broken (Linux)
        FS#1544 - Crash when selecting spline
        FS#1545 - File > Open: Crash on some Linux setups
        FS#1548 - Block > Attributes > Synchronize Attributes: exception
        FS#1550 - Block references: mirrored block references in 3rd party file
        FS#1551 - File > Bitmap Export: exception when image size too large
        FS#1553 - Modify > Break out Manual: exception with circles
        FS#1554 - Auto focus of options toolbar when entering numbers broken \ 
after Esc
        FS#1557 - Zero length lines not shown

3.16.5 (2017/02/09)

    QCAD Professional:
        Command line tools:
            dwg2maptiles:
                Add support for transparent background (-b \ 
"transparent"|"#FF000000"|"#FFFFFFFF")
            dwg2dwg:
                Add switch to change header variables (-s)
                Add switch to change dimension font (-n)
    Modify > Explode:
        Improve geometry of exploded texts from CXF line fonts
    Dimension:
        Add scale property for ordinate dimensions
    Platforms:
        macOS:
            Update to Qt 5.8.0
                fix accessibility related library dependency issues
    Bug fixes:
        FS#1528 - Block attributes: relationship with block reference lost after \ 
inserting from library
        FS#1529 - File > Save: error if dimension text size is zero
        FS#1530 - Draw > Circle > 3 Tangents: solutions not found
        FS#1536 - Draw > Polyline > Delete Node(s): crash when deleting \ 
2nd last node
        FS#1540 - Draw > Line > Parallel: Changing back to Auto has no effect