3.4 Known Problems
The toolkit was developed and tested under Linux, Solaris, Windows NT 4.0
using JDK 1.0.2 (Linux, Solaris), JDK 1.0.3 (Linux), JDK 1.0.4 (Solaris),
Netscape Navigator 3.02 (Linux, Solaris), Netscape Communicator 4.03 (Linux,
Solaris, Windows NT 4.0). I know about the following user interface problems
but do not know how to fix them because of bugs or limitations (features?) of
the different versions of the Java AWT.
- JDK PopUp Windows in Applets
- All versions of JDK aparently have serious
bugs in class
Window in applet mode, which makes it impossible to
determine the appropriate size of a popup window and to display the contents
such that they are visible under different browsers. The applet warning
string is displayed at different edges of the window (top, bottom,
left) by different browsers without adjusting the window size or
DAJ for JDK 1.0 uses a hack that should make the contents visible under most
browsers (JDK 1.0 appletviewer, Netscape 3.0/4.0 under Linux, Solaris, and
Windows NT 4.0) but yields oversized windows. DAJ for JDK 1.1 uses a hack that
makes the contents visible under JDK 1.1 appletviewer and gives even more ugly
- JDK 1.1 Scrolling
- In JDK 1.1, positioning scrollbars
apparently behaves differently from JDK 1.0, therefore the DAJ source is
different in both versions. Scrolling the visualization area in an application
developed with JDK 1.0 does not work correctly under JDK 1.1 (and certainly
not vice versa).
- JDK 1.0 X-Server Memory Consumption
- In JDK 1.0 under X-Windows, during
a visualization run, the memory consumption of the X-Server continuously grows
until the visualization is interrupted (by which free memory becomes instantly
available again). This may bring especially X-Terminals down to their knees
during longer visualization runs.
- JDK 1.0 Scrolling in Applets
- In JDK 1.0, on various browsers the size
of the vertical scrollbar slider does not match the size of the visualization
area. In Netscape 4.0 on Solaris, the slider is one pixel too small, in
Netscape 4.0 on Windows NT 4.0, the slider is about a frame width too small.
- JDK 1.0 PopUp Window Positions
- In JDK 1.0 the computation of a
component's offsets from its parent component apparently does not work
correctly. The pop-up windows do not appear in the specified locations but a
few pixels off.
- JDK 1.0 Window Resizing
- In JDK 1.0, resizing the visualization window
returns a zero coordinate in the corresponding event. Thus there is apparently
no possibility to determine the correct window position, if the window is
resized from the left upper corner. Popup windows appear in wrong places until
the window is moved.
- JDK 1.0 Window Closing
- In JDK 1.0, it is apparently not possible to
trigger an action when the user selects the menu item "Close" in a window's
frame. The window remains open.
- JDK 1.0 Visualization Window in Applets
- In JDK 1.0, there is apparently
no possibility to determine the position of an applet in absolute screen
coordinates. The visualization window thus pops up always in a fixed place.
- JDK 1.0 Help Menu
- In JDK 1.0 on Linux, setting help menus for
menu bars does not work. Thus the help menu is generally added as a normal
left-justified menu in DAJ for JDK 1.0.
- JDK Scrollbars
- In both versions of JDK, it is apparently not possible
to determine the height/width of a scrollbar before the component is created
to which the scrollbar is attached. Thus the visualization area is a bit
smaller than specified by the programmer in both dimensions (the area includes
both the horizontal and the vertical scrollbar).
- Netscape 4.0 Applet Redraw
- Under Netscape 4.0 on Windows, the
visualization area of an DAJ applet is sometimes not redrawn when the popup
window is closed.
- Netscape 4.0 Applet Stops
- Netscape 4.0 does not trigger the
method of an applet when the browser is iconified, thus the visualization
window remains open.
Maintainer: Wolfgang Schreiner
Last Modification: October 1, 1998