Improved message coloring, messageStatus display only for own messages

additionally loaded the message status icons smaller and (visually) hid
the vertical scrollbars (they can still be used, but cannot be seen).
Lastly checked all context menu functions for a NullPointerException, as
also no element can be selected when the context menu is created.

src/main/resources/css/base.css

@@ -26,6 +26,11 @@
 	-fx-background-color: transparent;
 }
 
+.scroll-bar:horizontal, .scroll-bar *, .scroll-bar:horizontal > *{
+	-fx-background-color: transparent;
+	-fx-text-fill: transparent;
+}
+
 .online {
 	-fx-text-fill: limegreen;
 }

src/main/resources/css/dark.css

@@ -7,7 +7,7 @@
 }
 
 .button {
-	-fx-background-color: darkviolet;
+	-fx-background-color: rgb(105.0,0.0,153.0);
 }
 
 .button:pressed {
@@ -23,15 +23,15 @@
 }
 
 .list-cell:selected, .list-cell:selected > *, .menu-item:hover {
-    -fx-background-color: darkviolet;
+    -fx-background-color: rgb(105.0,0.0,153.0);
 }
 
 .received-message {
-	-fx-background-color: seagreen;
+	-fx-background-color: gray;
 }
 
 .own-message {
-	-fx-background-color: gray;
+	-fx-background-color: #8fa88f;
 }
 
 .alert.information.dialog-pane, .alert.warning.dialog-pane, .alert.error.dialog-pane {

src/main/resources/css/light.css

@@ -7,10 +7,10 @@
 	-fx-text-fill: black;
 }
 
-.received-message {
-	-fx-background-color: lightgreen;
-}
-
-.own-message , .menu-item {
+.received-message, .menu-item {
 	-fx-background-color: lightgray;
 }
+
+.own-message {
+	-fx-background-color: lightgreen;
+}